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, t = input(), input()
s = (int(s[0]) * 10 + int(s[1])) * 60 + int(s[3]) * 10 + int(s[4])
t = (int(t[0]) * 10 + int(t[1])) * 60 + int(t[3]) * 10 + int(t[4])
for u in range(t):
    s -= 1
    if s == -1: s = 1439
print(s // 600, s // 60 % 10, ":", s % 60 // 10, s % 60 % 10, sep = "") 