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.
pt=input()#present time
sp=input()#sleeping time

pth=int(pt[0:2])
ptm=int(pt[3:5])

sph=int(sp[0:2])
spm=int(sp[3:5])

if spm<=ptm:
    pstm=(ptm-spm)
    if sph<=pth:
        psth=(pth-sph)
    elif sph>pth:
        psth=(24-(sph-pth))
else:
    pstm=(60-(spm-ptm))
    if sph<=pth:
        psth=(pth-sph-1)
    elif sph>pth:
        psth=(24-(sph-pth)-1)
if pstm<10:
    pstm="0"+str(pstm)
elif pstm>=10:
    pstm=str(pstm)

if psth<10:
    psth="0"+str(psth)
elif psth>=10:
    psth=str(psth)

s=psth+":"+pstm
print(s)
    