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()
a = int(s[0:2]) * 60 + int(s[3:5])
s = input()
b = int(s[0:2]) * 60 + int(s[3:5])
c = (a - b + (60 * 24)) % (60 * 24)
print(c // 60 // 10, c // 60 % 10, sep='', end=':')
print(c % 60 // 10, c % 60 % 10, sep='')