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.
# https://codeforces.com/problemset/problem/387/A
# 900

ch, cm = map(int, input().split(":"))
sh, sm = map(int, input().split(":"))

m = cm - sm
if m < 0:
    sh += 1
    m = 60 + m


h = ch - sh
if h < 0:
    h = 24 + h

print(f"{h:02}:{m:02}")