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.
h1, m1 = list(map(int, input().split(':')))
h2, m2 = list(map(int, input().split(':')))
if (m2 > m1):
	m1 += 60
	h1 -= 1
h1 -= h2
m1 -= m2
if (h1 < 0):
	h1 += 24
h = ''
m = ''
if (h1 < 10):
	h = '0'
h += str(h1)
if (m1 < 10):
	m = '0'
m += str(m1)
print(h, m, sep = ':', end = '\n')
