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.
sh,sm=map(int,input().split(':'))
th,tm=map(int,input().split(':'))
st,tt=sh*60+sm,th*60+tm
at=st-tt
if at>=0:
    hh = at // 60
    mm = at - hh * 60
    if len(str(hh)) == 1:
        hh = '0' + str(hh)
    if len(str(mm)) == 1:
        mm = '0' + str(mm)
if at<0:
    at=24*60 +at
    hh = at // 60
    mm = at - hh * 60
    if len(str(hh)) == 1:
        hh = '0' + str(hh)
    if len(str(mm)) == 1:
        mm = '0' + str(mm)
print(str(hh)+':'+str(mm))

