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,r=input(),input()
x=int(s[:2])-int(r[:2])
y=int(s[3:])-int(r[3:])
if(x<0):
    x=x+24
if(y<0):
    y=y+60
    x=x-1
xx,yy=str(x),str(y)
if(len(str(x))==1):
    if(x==0):
        xx=str(x)+'0'
    else:
        xx='0'+str(x)
if(len(str(y))==1):
    if(y==0):
        yy=str(y)+'0'
    else:
        yy='0'+str(y)
print(xx+':'+yy)
