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
from datetime import datetime, timedelta

def main():
	s = stdin.readline().strip()
	t = stdin.readline().strip()

	s = datetime.strptime(s, '%H:%M')
	t = datetime.strptime(t, '%H:%M')

	t = timedelta(hours = t.hour, minutes = t.minute)

	p = s - t

	print('{:02}:{:02}'.format(p.hour, p.minute))

if __name__ == '__main__': main()