30 users have solved this problem:

testcoder, user, horiseun, he, lion, Edward, Owen24, Yuuron, ndosh, programmer123, WenDidIAsk, dorian, Philip_cpp, loctildore, numb3r5, Matthewwww, Double_Slash, angus, Gomango999, Lithanium, SirLemonMeringue, ralismark, Ghetto, junkbot, TheEpicCowOfLife, gongy, ifndef_INDEED_TIS_TRUE_HPP_, newai, Uasoni2, JustinWang,