71 users have solved this problem:

he, eddieee, Gomango999, iamnumber4, dumpy, quanlin, evanl, horiseun, lion, user, hoangxuanbach, tbinhnoob, uylulu, dat123, tung, binbau10, harrysun2006, alexanyu, Yuuron, warren_huang, Edward, davinformatics, testcoder, tiko, Yichen, WenDidIAsk, ndosh, xiaoxiong, henryho2, jqxcz, programmer123, TnGn74, lupispuma74, dorian, Philip_cpp, moch, loctildore, numb3r5, ilt_cp_g, Sirhc_47, Double_Slash, Lucas4732, Uasoni2, Matthewwww, pony_joe1, ad_red, Ghetto, EternalFire, ralismark, jenny, Lithanium, OoogaDooga, Supermarine_Spitfire, dusky, ProperDiamond, PeaceOfCake, Chez, Nosna, Daniel_Sun, wap, doantronganh2008, GMICE_89khoa, pdao, BuMiTa, sssss, dungbetele, freecoder_123, longphuctran, Nhom9, hienng, Spectrum3563