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.
s=input()
t=input()
hrs=int(s[:2])-int(t[:2])
mins=int(s[3:])-int(t[3:])
if mins<0:
	mins+=60
	hrs-=1
if hrs<0:
	hrs+=24
hrs=str(hrs)
mins=str(mins)
if len(hrs)==1:
	hrs='0'+hrs
if len(mins)==1:
	mins='0'+mins
print(hrs+':'+mins)