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.
hour, mnt = map(int,input().split(":"))

durH, durM = map(int,input().split(":"))

resM = mnt - durM

sn = ((resM//(abs(resM)+.1))-abs(resM//(abs(resM)+.1)))/-2

resM += sn*60

resH = hour - durH - sn

resH += ((resH//(abs(resH)+.1))-abs(resH//(abs(resH)+.1)))*-12

print(f"{str(int(resH)).zfill(2)}:{str(int(resM)).zfill(2)}")