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 sys
import math
import heapq
import random
import collections
import datetime

def main():
    # sys.stdin = open('input.txt', 'r')
    # sys.stdout = open('output.txt', 'w')

    t1 = list(map(int, input().strip().split(':')))
    t2 = list(map(int, input().strip().split(':')))

    t1_ = datetime.timedelta(hours=t1[0], minutes=t1[1])
    t2_ = datetime.timedelta(hours=t2[0], minutes=t2[1])

    t3_ = t1_- t2_
    s = str(t3_)

    if len(s[-8:-3]) == 4:
        print('0'+s[-8:-3])

    else:
        print(s[-8:-3])
        
    # sys.stdin.close()
    # sys.stdout.close()

if __name__ == '__main__':
    main()
