s = list(map(int,input().split(":"))) e = list(map(int,input().split(":"))) S = s[0]*60*60+s[1]*60+s[2] E = e[0]*60*60+e[1]*60+e[2] T = (E-S + 24*60*60) % (24*60*60) if T == 0: T = 24*60*60 print("%02d:%02d:%02d" % (T//3600,(T%3600)//60,T%60))