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.
h, s = list(map(int, input().split(":")))
h1, s1 = list(map(int, input().split(":")))
minit = 60*h+s
a = 60*h1+s1
b = minit - a
c = b // 60
d = b % 60
if c < 0:
    c = 24 + c
elif c < 0:
    d = 60 + b
print("{}:{}".format(str(c).zfill(2),str(d).zfill(2)))