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.
import sys
input = sys.stdin.readline

s = list(map(int, input()[:-1].split(':')))
t = list(map(int, input()[:-1].split(':')))

a, b = s[0] - t[0], s[1] - t[1]
if b < 0:
    b += 60
    a -= 1

if a < 0:
    a += 24

if 0 <= a < 10:
    a = '0' + str(a)
else:
    a = str(a)

if 0 <= b < 10:
    b = '0' + str(b)
else:
    b = str(b)
print(a + ':' + b)
