# -*- coding: utf-8 -*-
"""
No.652 E869120 and TimeZone
https://yukicoder.me/problems/no/652

"""
import sys
from sys import stdin
input = stdin.readline


def main(args):
    a, b, S = input().split()
    a = int(a)
    b = int(b)
    S = float(S[3:])

    japanese_time = a * 60 + b
    time_diff = int(S * 60)

    ans = japanese_time + time_diff - 540
    if ans < 0:
        ans += 60 * 24
    elif ans >= 60 * 24:
        ans -= 60 * 24

    hh = ans // 60
    mm = ans % 60
    print('{:02d}:{:02d}'.format(hh, mm))


if __name__ == '__main__':
    main(sys.argv[1:])