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.
sh,sm=map(int,input().split(":"))
th,tm=map(int,input().split(":"))
h,m=0,0
if sm<tm:
	m=60+(sm-tm)
	h-=1
else:
	m=sm-tm
if sh<th:
	h+=24+(sh-th)
else:
	h+=sh-th
if len(str(h))==1:
	hh="0"+str(h)
else:
	hh=str(h)
if len(str(m))==1:
	mm="0"+str(m)
else:
	mm=str(m)
print(hh,":",mm,sep="")