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

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


def decode_time(S):
    S = S[3:]
    if not '.' in S:
        return int(int(S) * 60)
    else:
        hh, mm = S.split('.')
        hh = int(hh) * 60
        mm = int(mm) * 6
        if S[0] == '-':
            return hh - mm
        else:
            return hh + mm


def main(args):
    a, b, S = input().split()
    a = int(a)
    b = int(b)
    japanese_time = a * 60 + b
    time_diff = decode_time(S)

    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:])