66 users have solved this problem:

ja_kingy, boboquack, turtlecoder, ryno, he, numb3r5, evanl, ngrace, Guchi42, Gomango999, someone, ch13, dumpy, brchen, m012444m213, pichu, thenymphsofdelphi, laeequejamdar, iiliffe, trangim, henryho2, KarL06, xiaoxiong, bear1212, sundude, munux, ar88lo, zaneyu, lilu, phoebe, lion, Bean, testcoder, hhyau, user, ETK, horiseun, Ghetto, Magikarp4000, awu, gaulle, dorian, Uasoni2, yixiu, programmer123, ndosh, Philip_cpp, caterpillow, Lithanium, BigD, SirLemonMeringue, Vedang, Double_Slash, dusky, BurwoodChenFamily, chchn2507, Matthewwww, davinformatics, blx330, OneT_Chen, aerobull42, finehaveanormalusername, amanda, newai, meisean2009, admini,