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()
a,b,res=int(s[0:2])*60+int(s[3:]),int(t[0:2])*60+int(t[3:]),0
if a<b:
  res=1440+a-b
else:
  res=a-b
s1=res//60
s2=res-s1*60
ans=''
if s1<10:
  ans+='0'+str(s1)
else:
  ans+=str(s1)
ans+=':'
if s2<10:
  ans+='0'+str(s2)
else:
  ans+=str(s2)
print(ans)