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.
t1=input().split(':')
t2=input().split(':')
x1=int(t1[0])
x2=int(t1[1])
x3=int(t2[0])
x4=int(t2[1])
#x1:x2
#x3:x4
if x1>=x3 and x2>=x4:
    mins=str(x1-x3)
    hours=str(x2-x4)
    if len(mins)==1:
        mins='0'+mins
    if len(hours)==1:
        hours='0'+hours
    print(mins+':'+hours)
elif x1<=x3 and x2<=x4:
    mins=str(x1+24-x3)
    hours=str((x2-x4+60)%60)
    if len(mins)==1:
        mins='0'+mins
    if len(hours)==1:
        hours='0'+hours
    print(mins+':'+hours)
elif x1<=x3 and x2>=x4:
    mins=str(x1+24-x3)
    hours=str((x2-x4)%60)
    if len(mins)==1:
        mins='0'+mins
    if len(hours)==1:
        hours='0'+hours
    print(mins+':'+hours)
else:
    mins=str(x1-x3)
    hours=str((x2-x4+60)%60)
    if len(mins)==1:
        mins='0'+mins
    if len(hours)==1:
        hours='0'+hours
    print(mins+':'+hours)
