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.
a = list(input().split(':'))
b = list(input().split(':'))
flag = False
if a[1] < b[1]:
    flag = True
a[0] = int(a[0]) + 24
a[1] = int(a[1]) + 60
hour = (int(a[0])-int(b[0]))%48
mins = (int(a[1])-int(b[1]))%60
if flag:
    hour -= 1
print(str(hour).zfill(2), end=':')
print(str(mins).zfill(2))
