Presidential candidates, Ukrainian President Petro Poroshenko, centre right, kneels as he kisses a flag as popular comedian Volodymyr Zelenskiy, left, kneels on stage during their debate in the weekend presidential run-off at the Olympic stadium in Kiev, Ukraine, Friday, April 19, 2019. A comedian leading Ukraine???s presidential race and the incumbent faced off in a debate at the nation???s largest sports arena Friday, fiercely trading accusations two days before the runoff. (AP Photo/Efrem Lukatsky)