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.
s=list(map(int,input().split(":")))
t=list(map(int,input().split(":")))
c=0
if t[1]>s[1]:
	s[1]+=60
	s[1]-=t[1]
	c+=1
else:
	s[1]-=t[1]
if s[0]-(t[0]+c)<0:
	d=t[0]+c-s[0]
	s[0]=24-d
else:
	s[0]-=(t[0]+c)
s=list(map(str,s))
for i in range(2):
	if len(s[i])==1:
		s[i]="0"+s[i]
print(":".join(s))