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.

 # ///==========Libraries, Constants and Functions=============///
#mkraghav
import sys

inf = float("inf")
mod = 1000000007


def get_array(): return list(map(int, sys.stdin.readline().split()))


def get_ints(): return map(int, sys.stdin.readline().split())


def input(): return sys.stdin.readline()

def int1():return int(input())

import string

import math


from itertools import combinations
# ///==========MAIN=============///


def main():
    s1=input()
    s2=input()
    x1=int(s1[:2])
    x2=int(s1[3:])
    y1=int(s2[:2])
    y2=int(s2[3:])


    x3=x1-y1
    if x3<0:
        x3=24+x3
    y=x2-y2
    if x3<10:
        x3=str(0)+str(x3)
    if y<10:
        y=str(0)+str(y)
    print(str(x3)+':'+str(y))





















if __name__ == "__main__":
    main()
