import math

a, b, s = input().split()
a = int(a)
b = int(b)
utc = a * 60 + b - 540
diff = "".join(filter(lambda x:x.isdigit() or x == ".", s))
diff = float(diff)
s = list(s)

res = 0
if s[3] == "+":
    d = diff * 60
    res = utc + math.ceil(d)
elif s[3] == "-":
    d = diff * 60 * (-1)
    res = utc + math.ceil(d)

if res >= 1440:
    h = res // 60 - 24
    m = res % 60
elif res <=0:
    h = res // 60 + 24
    m = res % 60
else:
    h = res // 60
    m = res % 60

print(f'{h:0=2}:{m:0=2}')