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 = input()
t = input()
mms = int(s[:2]) * 60 + int(s[3:])
mmt = int(t[:2]) * 60 + int(t[3:])
diff = (mms + 1440 - mmt) % 1440
h = diff // 60
m = diff % 60
print(str(h).zfill(2) + ':' + str(m).zfill(2))