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.
s1=input()
s2=input()
ans1=int(s1[:2])-int(s2[:2])
ans2=int(s1[3:])-int(s2[3:])
if ans2>=0:
     k2="0"+str(ans2)
     if ans1>=0:
          k1="0"+str(ans1)
          print(k1[-2:]+":"+k2[-2:])
     else:
          ans1+=24
          k1="0"+str(ans1)
          print(k1[-2:]+":"+k2[-2:])
else:
     ans2+=60
     ans1-=1
     k2="0"+str(ans2)
     if ans1>=0:
          k1="0"+str(ans1)
          print(k1[-2:]+":"+k2[-2:])
     else:
          ans1+=24
          k1="0"+str(ans1)
          print(k1[-2:]+":"+k2[-2:])
     
     
          
          
