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()
t2 = int(t[0:2]) * 60 + int(t[3:])
s2 = int(s[0:2]) * 60 + int(s[3:])
x = 1440
if t2 > s2:
	x += s2 - t2
else:
	x = s2 - t2
h1 = x // 60
m1 = x % 60
h = str(h1)
m = str(m1)
if h1 < 10:
	h = "0" + str(h1)
if m1 < 10:
	m = "0" + str(m1)
print(h+":"+m)