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(':')
s[0]=int(s[0])
s[1]=int(s[1])
t=input().split(':')
t[0]=int(t[0])
t[1]=int(t[1])
def v(n):
    n=str(n)
    if len(n)==1:
        return '0'+n
    else:
        return n    
if s[0]>=t[0] and s[1]>=t[1]:
    print(v(s[0]-t[0])+':'+v(s[1]-t[1]))
elif s[0]>t[0] and s[1]<t[1]:
    print(v(s[0]-t[0]-1)+':'+v(s[1]+60-t[1]))
elif s[0]==t[0] and s[1]<t[1]:
    print('23'+':'+v(s[1]+60-t[1]))
elif s[0]<t[0] and s[1]>=t[1]:
    print(v(24-(t[0]-s[0]))+':'+v(s[1]-t[1]))   
elif s[0]<t[0] and s[1]<t[1]: 
    print(v(24-(t[0]-s[0])-1)+':'+v(60+s[1]-t[1]))        