15.py

n, m, t = int(input()), int(input()), int(input())
n += t // 60
m += t % 60
while m > 59:
    m -= 60
    n += 1
while n > 23:
    n -= 24

s = ""
for arg in [n, m]:
    if arg < 10:
        s += "0"
    s += str(arg)
s = s[:2] + ":" + s[2:]
print(s)