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()
h1=int(s1[0:2])
m1=int(s1[3:5])
h2=int(s2[0:2])
m2=int(s2[3:5])
h=0
m=0
if (m1>=m2):
  m=m1-m2
  if (h1>=h2):
     h=h+h1-h2
  else:
     h=h+(24-(h1-h2))
else:
  m=60-(m2-m1)
  if (h1>h2):
     h=h+h1-h2-1
  else:
     h=h+(24-(h1-h2)-1)
a=''
if (h//10>=1):
  a=a+str(h)
else:
  a=a+'0'+str(h)
a=a+':'
if (m//10>=1):
  a=a+str(m)
else:
  a=a+'0'+str(m)
print(a)