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(':'))))
diff1 = t1[0] - t2[0]
diff2 = t1[1]- t2[1]
if diff1 < 0:
    diff1+=24
if diff2 < 0:
    diff2+=60
    diff1-=1
s = str(diff1).zfill(2) + ':' + str(diff2).zfill(2)
print(s)