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.
a=input()

b=input()


p=int(a[0:2])-int(b[0:2])

if p<0:
    p = 24 + p


m = int(a[3:])-int(b[3:])

if m<0:
    m= 60+m
    p-=1


if len(str(p))==1:
    if p==0:
        p = str(p)+'0'
    else:
        p= '0'+str(p)
if len(str(m))==1:
    if m==0:
        m= str(m)+'0'
    else:
        m= '0' + str(m)


    
print(str(p)+':'+str(m))
