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()
t=input()
c=0
if int(s[3:])-int(t[3:])>=0:
    t1=str(int(s[3:])-int(t[3:]))
    if int(t1)<10:t1='0'+t1
else:
    t1=int(s[3:])-int(t[3:])
    t1=str(60+t1)
    if int(t1)<10:t1='0'+t1
    c=1
if c==1:
    if int(s[:2])-int(t[:2])-1>=0:
        t2=str(int(s[:2])-int(t[:2])-1)
        if int(t2)<10:t2='0'+t2
    else:
        t2=int(s[:2])-int(t[:2])-1
        t2=str(24+t2)
        if int(t2)<10:t2='0'+t2
else:
    if int(s[:2])-int(t[:2])>=0:
        t2=str(int(s[:2])-int(t[:2]))
        if int(t2)<10:t2='0'+t2
    else:
        t2=int(s[:2])-int(t[:2])
        t2=str(24+t2)
        if int(t2)<10:t2='0'+t2
ans=t2+':'+t1
print(ans)
