A demonstrator blows a whistle during a protest in front of the National assembly building in Belgrade on April 4, 2017. Thousands of mostly young people joined protests on April 4, 2017 for a second consecutive night in several Serbian cities against Prime Minister Aleksandar Vucic being elected the country's next president. / AFP PHOTO / ANDREJ ISAKOVIC (Photo credit should read ANDREJ ISAKOVIC/AFP/Getty Images)