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.
import math
import bisect

from math import gcd, floor, sqrt, log
from collections import defaultdict as dd

I = lambda: int(input())
tup = lambda: map(int, input().split())
lst = lambda: list(map(int, input().split()))

t = 1
#t = I()

while t:

    h1, m1 = map(int, input().split(':'))
    h2, m2 = map(int, input().split(':'))

    m = m1 - m2
    h = h1 - h2

    if m < 0:
        m += 60
        h -= 1
    
    if h < 0:
        h += 24

    print("{0:02d}:{1:02d}".format(h,m))

    



    t -= 1


    