71 users have solved this problem:

testcoder, ndosh, programmer123, bear1212, angus, lion, user, Ghetto, grossly_overconfident, Magikarp4000, horiseun, awu, BigD, SirLemonMeringue, justin_g_20, Salamander, davinformatics, loctildore, evanl, phoebe, TheEpicCowOfLife, henryho2, RileyO, dorian, tomister99, dumpy, numb3r5, xiaoxiong, sheep, lilu, ImMcHe, KarL06, Uasoni2, Philip_cpp, Matthewwww, Gomango999, abyssmall, caterpillow, PeaceOfCake, JerryTheBerry, Nosna, Andy, Lithanium, OoogaDooga, Double_Slash, WenDidIAsk, finehaveanormalusername, ad_red, dusky, Vedang, Supermarine_Spitfire, jenny, chchn2507, aerobull42, HappyCapybara, Conan, blx330, AllOuttaLeeks, ja_kingy, Nonoze, jbroeksteeg, meisean2009, mtpedro, nosna, Zybg, hhhyh, amanda, newai, liangjeremy, a_dude_who_fails_to_register, OneT_Chen,