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.
a,b=input().split(':'),input().split(':')
d=(int(a[1])-int(b[1]))%60
if a[1]<b[1]:
	if a[0] <= b[0]:
		c=(int(a[0])-int(b[0])-1)%24
	else:
		c=int(a[0])-int(b[0])-1
else:
	if a[0]<b[0]:
		c=(int(a[0])-int(b[0]))%24
	else:
		c=int(a[0])-int(b[0])

if c<10:
	c='0'+str(c)
if d<10:
	d='0'+str(d)
print('{}:{}'.format(c,d))

  	 	  				        								   	