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.
t1 = list(map(int, input().split(':')))
t2 = list(map(int, input().split(':')))
t1[0] -= t2[0]
t1[1] -= t2[1]
if t1[1] < 0:
    t1[0] -= 1
    t1[1] += 60
if t1[0] < 0:
    t1[0] += 24
print("%02d:%02d" % (t1[0], t1[1]))