h, s, tz = input().split()
h, s = map(int, [h,s])

tz = math.ceil(float(tz[3:])*60)

s = (60*h+s-540+tz) % (24*60)

h, s = map(str, [s // 60, s % 60])
if len(s) == 1:
    s = "0" + s
if len(h) == 1:
    h = "0" + h
print(h+":"+s)