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(':')
a=int(s[0])
b=int(s[1])

s=input().split(':')
x=int(s[0])
y=int(s[1])

b=b-y
if b<0:
	b=b+60
	a-=1
a=a-x
if a<0:
	a=a+24

if a<10:
	print('0',end="")
print(a,end="")

print(":",end="")
if b<10:
	print(0,end="")
print(b,end="")
