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.
t1=input().split(':')
t2=input().split(':')
h1=int(t1[0])
m1=int(t1[1])
h2=int(t2[0])
m2=int(t2[1])
if(h1<h2 or(h1==h2 and m1<m2)):
    h1+=24
h1=h1-h2
m1=m1-m2
if(m1<0):
    h1-=1
    m1+=60
print('%02d:%02d'%(h1,m1))