A combination photo shows a Girl Scout losing her balance in her camp chair around a pretend campfire as U.S. President Barack Obama and the first lady welcome the scouts to a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

A Girl Scout loses her balance in her camp chair around a pretend campfire as U.S. President Barack Obama and the first lady welcome the scouts to a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

A Girl Scout loses her balance in her camp chair around a pretend campfire as U.S. President Barack Obama and the first lady welcome the scouts to a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

A Girl Scout loses her balance in her camp chair around a pretend campfire as U.S. President Barack Obama and the first lady welcome the scouts to a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst TPX IMAGES OF THE DAY

U.S. President Barack Obama and first lady Michelle Obama sit at a pretend campfire during a camp-out for Girl Scouts on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama (C) pretends to warm her hands by a "campfire" of electric lanterns as she and President Barack Obama welcome Girl Scouts for a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama reacts to a rush of Girl Scouts coming at him for a group hug as he and the first lady welcomed them for a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama and first lady Michelle Obama joke around as they sit at a pretend campfire during a camp-out for Girl Scouts on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama and first lady Michelle Obama joke around as they sit at a pretend campfire during a camp-out for Girl Scouts on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama looks back as he returns to the White House after he and the first lady welcomed Girl Scouts for a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama (C) and first lady Michelle Obama (2nd R) look through a telescope as they welcomed Girl Scouts for a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama returns to the White House he and the first lady welcomed Girl Scouts for a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama reacts to a rush of Girl Scouts coming at him for a group hug as he and the first lady welcomed them for a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama (2nd L) and first lady Michelle Obama (3rd L) look through a telescope as they welcomed Girl Scouts for a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama makes note of first lady Michelle Obama's dance moves as they sing with Girl Scouts during a camp out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama and first lady Michelle Obama sing with Girl Scouts during a camp out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama makes note of first lady Michelle Obama's dance moves as they sing with Girl Scouts during a camp out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama makes a silly face as he and first lady Michelle Obama sing with Girl Scouts during a camp out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama reacts as Girl Scouts rush to him for a group hug as he and first lady Michelle Obama (not pictured) welcome them for a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn in celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. President Barack Obama reacts as Girl Scouts rush to him for a group hug as he and first lady Michelle Obama (not pictured) welcome them for a camp-out on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn in celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst TPX IMAGES OF THE DAY

U.S. first lady Michelle Obama (R), introduced by Aniyah King (L), a Girl Scout from Virginia, welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama (R), introduced by Aniyah King (C), a Girl Scout from Virginia, and National President of the Girl Scouts of the USA Kathy Hannan (L), welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

A Girl Scout makes her way up a climbing wall as part of the "Let's Move Outside" camp-out on the South Lawn of the White House in Washington June 30, 2015. After a welcome from U.S. first lady Michelle Obama, the group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama (5th L) welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plans to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama participates at a knot-tying station as she welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama (C) participates at a knot-tying station as she welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama (C) gives out hugs as she welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama participates in a knot-tying session as she welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

U.S. first lady Michelle Obama welcomes a group of Girl Scouts to the "Let's Move Outside" campout on the South Lawn of the White House in Washington June 30, 2015. A group of 50 fourth-grade Girl Scouts plan to spend the night in camping tents on the lawn, a celebration of the scouting movement and the National Park Service centennial. REUTERS/Jonathan Ernst 

A member of the Girls Scouts of America walks next to graves while placing U.S. flags at Cypress Hills National Cemetery in Brooklyn, New York May 23, 2015. The annual "Flags-In" ceremony is held ahead of Memorial Day to honor the nation's fallen members of the military. REUTERS/Eduardo Munoz

Pope Francis talks to a girl scout during his pastoral visit to the Church of S. Maria Regina Pacis in Ostia, near Rome, May 3, 2015. REUTERS/Giampiero Sposito 

Pope Francis changes his skull cap as he talks to a girl scout during his pastoral visit to the Church of S. Maria Regina Pacis in Ostia, near Rome, May 3, 2015. REUTERS/Giampiero Sposito 

A girl scout holds a Greek national flag ahead of a student parade in Athens March 24, 2015, a day before a military parade to mark Greece's Independence Day. Greece said it will present a package of reforms to its euro zone partners by next Monday in hope of unlocking aid to help it deal with a cash crunch and avoid default. REUTERS/Alkis Konstantinidis TPX IMAGES OF THE DAY

U.S. President Barack Obama gives a group-hug to six-year-old Girl Scouts from Tulsa, Oklahoma, who used Lego pieces to create a battery-powered page turner to help people who are paralyzed or have arthritis, as he plays host to the 2015 White House Science Fair at the White House in Washington, March 23, 2015. REUTERS/Jonathan Ernst 

U.S. President Barack Obama speaks with a group of six-year-old Girl Scouts from Tulsa, Oklahoma, who used Lego pieces to create a battery-powered page turner to help people who are paralyzed or have arthritis, as he plays host to the 2015 White House Science Fair at the White House in Washington, March 23, 2015. REUTERS/Jonathan Ernst 

U.S. President Barack Obama stands with a group of six-year-old Girl Scouts from Tulsa, Oklahoma, who used Lego pieces to create a battery-powered page turner to help people who are paralyzed or have arthritis, as he plays host to the 2015 White House Science Fair at the White House in Washington, March 23, 2015. REUTERS/Jonathan Ernst 

U.S. President Barack Obama reacts to a group of six-year-old Girl Scouts from Tulsa, Oklahoma, who used Lego pieces to create a battery-powered page turner to help people who are paralyzed or have arthritis, as he plays host to the 2015 White House Science Fair at the White House in Washington, March 23, 2015. REUTERS/Jonathan Ernst 

U.S. President Barack Obama greets a group of six-year-old Girl Scouts from Tulsa, Oklahoma, who used Lego pieces to create a battery-powered page turner to help people who are paralyzed or have arthritis, as he plays host to the 2015 White House Science Fair at the White House in Washington, March 23 2015. REUTERS/Jonathan Ernst 

Lynyrd Puyat shows one gram of the Girl Scout Cookies strain of marijuana that he purchased for $15 using a ZaZZZ vending machine at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. Vending machines selling medical marijuana opened for business in Seattle on Tuesday, in what the company providing them billed as a first-in-the-state innovation that it expects to expand to other cities and states where pot is legal as medicine. Puyat was the first to use the machines. REUTERS/David Ryder (UNITED STATES - Tags: DRUGS SOCIETY HEALTH BUSINESS) 

Lynyrd Puyat uses a ZaZZZ vending machine to purchase one gram of the Girl Scout Cookies strain of marijuana for $15 at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. Vending machines selling medical marijuana opened for business in Seattle on Tuesday, in what the company providing them billed as a first-in-the-state innovation that it expects to expand to other cities and states where pot is legal as medicine. Puyat was the first to use the machines. REUTERS/David Ryder (UNITED STATES - Tags: DRUGS SOCIETY HEALTH BUSINESS) 

Lynyrd Puyat uses a ZaZZZ vending machine to purchase one gram of the Girl Scout Cookies strain of marijuana for $15 at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. Vending machines selling medical marijuana opened for business in Seattle on Tuesday, in what the company providing them billed as a first-in-the-state innovation that it expects to expand to other cities and states where pot is legal as medicine. Puyat was the first to use the machines. REUTERS/David Ryder (UNITED STATES - Tags: DRUGS SOCIETY HEALTH BUSINESS) 

Britain's Catherine, Duchess of Cambridge, teaches a girl how to use chopsticks as she meets with children at the newly established 23rd Poplar Beaver Scout Colony in east London December 16, 2014. REUTERS/Ben Stansall/Pool (BRITAIN - Tags: ROYALS) 

Britain's Catherine, Duchess of Cambridge, teaches a girl how to use chopsticks as she meets with children at the newly established 23rd Poplar Beaver Scout Colony in east London December 16, 2014. REUTERS/Ben Stansall/Pool (BRITAIN - Tags: ROYALS) 

A Girl Scout color guard presents the colors at the morning plenary session of the Values Voter Summit in Washington September 26, 2014. REUTERS/Gary Cameron (UNITED STATES - Tags: POLITICS ELECTIONS RELIGION) 

A Girl Scout color guard presents the colors at the morning plenary session of the Values Voter Summit in Washington September 26, 2014. REUTERS/Gary Cameron (UNITED STATES - Tags: POLITICS ELECTIONS RELIGION) 

A Girl Scout color guard carries in the colors at the morning plenary session of the Values Voter Summit in Washington September 26, 2014. REUTERS/Gary Cameron (UNITED STATES - Tags: POLITICS ELECTIONS RELIGION) 

U.S. President Barack Obama bends down to listen to a team of Girl Scouts USA from Tulsa, Oklahoma, explaining their flood proof bridge design as he hosts the 2014 White House Science Fair in the Blue Room at the White House in Washington, May 27, 2014. Seen here are Avery Dodson (L-R), Miriam Schaffer, Lucy Claire Sharp, Natalie Hurley and Clair Winton. REUTERS/Larry Downing (UNITED STATES - Tags: POLITICS SCIENCE TECHNOLOGY) 

Volunteers from the Girl Scouts of Greater Los Angeles, Daisy Wright (R), 13, and Katie Mulligan, 13, decorate the K9s4COPs Tournament of Roses Parade float, themed " Working Together for safer Communities", at Fiesta Parade Floats in Irwindale, California December 30, 2013. The float will be entered in the 125th Rose Parade, which will take place on January 1, 2014, in Pasadena, California. REUTERS/Kevork Djansezian (UNITED STATES - Tags: SOCIETY) 

Yemeni girl scouts salute as they march during a ceremony marking the anniversary of the September 1962 revolution in Sanaa September 25, 2013. The ceremony marked the 51st anniversary of the revolution that toppled the regime of the Hameed al-Deen family in northern Yemen on September 26, 1962. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: POLITICS ANNIVERSARY) 

Yemeni girl scouts wave Yemeni flags as they march during a ceremony marking the anniversary of the September 1962 revolution in Sanaa September 25, 2013. The ceremony marked the 51st anniversary of the revolution that toppled the regime of the Hameed al-Deen family in northern Yemen on September 26, 1962. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: ANNIVERSARY POLITICS) 

Ecuador's President Rafael Correa (R) salutes a girl scout as he attends the Inter-American Boys Scouts summit in Buenos Aires September 19, 2013. Correa is on a one-day visit to Argentina. REUTERS/Marcos Brindicci (ARGENTINA - Tags: POLITICS) 

A Girl Scouts Brownie runs through rows of graves at the Los Angeles National Cemetery during a flag placement event to commemorate Memorial Day weekend in Los Angeles, California, May 25, 2013. REUTERS/Jonathan Alcorn (UNITED STATES - Tags: SOCIETY ANNIVERSARY) 

Elli Jones, a Girl Scouts Brownie, salutes after placing a flag on a gravesite of a U.S. military veteran at the Los Angeles National Cemetery during a flag placement event to commemorate Memorial Day weekend in Los Angeles, California, May 25, 2013. REUTERS/Jonathan Alcorn (UNITED STATES - Tags: SOCIETY ANNIVERSARY) 

Members of a Mariner Girl Scout troop salute at gravesites of U.S. military veterans at the Los Angeles National Cemetery during a flag placement event to commemorate Memorial Day weekend in Los Angeles, California, May 25, 2013. REUTERS/Jonathan Alcorn (UNITED STATES - Tags: SOCIETY ANNIVERSARY) 

Viaenne Tom, 6, a girl scout, places a flag at a grave at Cypress Hills National Cemetery in Brooklyn, New York May 25, 2013. The annual "Flags-In" ceremony is held ahead of Memorial Day to honor the nation's fallen members of the military. Flags will be placed at more than 220,000 graves. REUTERS/Eduardo Munoz (UNITED STATES - Tags: MILITARY SOCIETY ANNIVERSARY) 

A girl scout of the 233 pack from Brooklyn carries flags to be placed at graves at Cypress Hills National Cemetery in Brooklyn, New York May 25, 2013. The annual "Flags-In" ceremony is held ahead of Memorial Day to honor the nation's fallen members of the military. Flags will be placed at more than 220,000 graves. REUTERS/Eduardo Munoz (UNITED STATES - Tags: MILITARY SOCIETY ANNIVERSARY) 

Viaenne Tom, 6, a girl scout, places a flag at a grave at Cypress Hills National Cemetery in Brooklyn, New York May 25, 2013. The annual "Flags-In" ceremony is held ahead of Memorial Day to honor the nation's fallen members of the military. Flags will be placed at more than 220,000 graves. REUTERS/Eduardo Munoz (UNITED STATES - Tags: MILITARY SOCIETY ANNIVERSARY TPX IMAGES OF THE DAY)