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()

hs = int(s[:2])
ms = int(s[3:5])
ht = int(t[:2])
mt = int(t[3:5])

hr = 0
mr = 0
if hs < ht:
    hr = 24 - abs(hs - ht)
else:
    hr = hs - ht

if ms < mt:
    mr = 60 - abs(ms - mt)
    hr = hr - 1 if hr > 0 else 23
else:
    mr = ms - mt

print(str(hr).zfill(2) + ':' + str(mr).zfill(2))