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,b=(map(int,input().split(':')))
c,d=(map(int,input().split(':')))
t1 = a*60+b
t2 = c*60+d
if t1>t2:
    t3 = t1-t2
else:
    t3 = 24*60+t1-t2
print(f'%02d:%02d'%(t3//60,t3%60))