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.
from sys import stdin; inp = stdin.readline
from math import dist, ceil, floor, sqrt, log
from collections import defaultdict, Counter
def IA(): return list(map(int, inp().split()))
def FA(): return list(map(float, inp().split()))
def SA(): return inp().split()
def I(): return int(inp())
def F(): return float(inp())
def S(): return input()
def O(l:list): return ' '.join(map(str, l))

def main():
    ch, cm = map(int, S().split(':'))
    dh, dm = map(int, S().split(':'))
    dmins = dm + dh*60
    ctime = ch*60 + cm 
    x = ctime - dmins
    h, m = divmod(x, 60)
    h = 24+h if h<0 else h 
    h = str(h)
    m = str(m)
    if len(h)==1: h = '0'+h 
    if len(m)==1: m = '0'+m
    return h+':'+m
        
if __name__ == '__main__':
    print(main())