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
# sys.stdin=open("input.txt","r")
# sys.stdout=open("output.txt","w")
x,y = map(int,input().split(":"))
h,m = map(int,input().split(":"))
if (y-m)<0:
    x=x-1
    if (x<0):
        x = 24+x
    y = 60+(y-m)
else:
    y = y-m
    
    
    
if (x-h)<0:
    x = 24+(x-h)
else:
    x = x - h
    
if x<9:
    hr = "0" + str(x)
if y<9:
    mi = "0" + str(y)
    
    
print(hr + ":" + mi)