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.
from functools import reduce
from operator import *
from math import *
from sys import *
from string import *
from collections import *
setrecursionlimit(10**7)
dX= [-1, 1, 0, 0,-1, 1,-1, 1]
dY= [ 0, 0,-1, 1, 1,-1,-1, 1]
RI=lambda: list(map(int,input().split()))
RS=lambda: input().rstrip().split()
#################################################
h1,m1=map(int,input().split(':'))
h2,m2=map(int,input().split(':'))
m1-=m2
if m1<0:
    h1-=1
h1-=h2
if h1<0:
    h1+=24
h1,m1=str(h1),str(m1)
if len(h1)==1:  h1='0'+h1
if len(m1)==1:  m1='0'+m1
print(h1+':'+m1)








