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,t=input(),input()
h1=int(s[0:2])
h2=int(t[0:2])
m1=int(s[3:])
m2=int(t[3:])
m3=m1-m2
if(m3<0):
    m3=60+m1-m2
    h3=h1-h2-1
    if(h3<0):
        h3=24+h3
else:
    h3=h1-h2
    if(h3<0):
        h3+=24
if(h3<10 and m3<10):
    print('0',h3,':','0',m3,sep="")
elif(h3>=10 and m3<10):
    print(h3,':','0',m3,sep="")
elif(h3<10 and m3>=10):
    print('0',h3,':',m3,sep="")
else:
    print(h3,':',m3,sep="")