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().split(":")
t = input().split(":")
h = [int(s[0]), int(t[0])]
m = [int(s[1]), int(t[1])]

h[0] -= h[1];
m[0] -= m[1];
if m[0] < 0:
    m[0] += 60
    h[0] -= 2
if h[0] < 0:
    h[0] += 24;
print(f'{h[0]:02}', ":", f'{m[0]:02}', sep = "")