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.
'''input
00:01
00:00
'''
s, t = list(map(int, input().split(":"))), list(map(int, input().split(":")))
a, b, c, d = s[0], s[1], t[0], t[1]
x = []
if b >= d:
	x.append(str(b-d).zfill(2))
else:
	x.append(str((b-d) % 60).zfill(2))
	a -= 1
x.insert(0, str((a-c) % 24).zfill(2))
print(":".join(x))







