George woke up and saw the current time *s* on the digital clock. Besides, George knows that he has slept for time *t*. 

Help George! Write a program that will, given time *s* and *t*, determine the time *p* when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
The first line contains current time *s* as a string in the format "hh:mm". The second line contains time *t* in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ *hh* ≤ 23, 00 ≤ *mm* ≤ 59.
'''
# Submitted By M7moud Ala3rj
Don't Copy This Code, CopyRight . [email protected] © 2022-2023 :)
'''
# Problem Name = "George and Sleep"
# Class: A

import sys

#sys.setrecursionlimit(2147483647)
input = sys.stdin.readline
def printf(*args, end='\n', sep=' ') -> None:
    sys.stdout.write(sep.join(map(str, args)) + end)

def Solve():
    s = list(map(int, input().split(":")))
    t = list(map(int, input().split(":")))
    s = s[0]*60+s[1]
    t = t[0]*60+t[1]
    print(str((s-t)//60+24*((s-t)//60<0)).zfill(2)+":"+str((s-t)%60).zfill(2))


if __name__ == "__main__":
    # for t in range(int(input())):
        Solve()