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()
k=0
r=0
for i in s:
    if i==':':
        break
    else:
        if int(i)!=0:
            k+=int(i)*60
k+=int(s[-1])
k+=int(s[-2])*10
    
for i in t:
    if i==':':
        break
    else:
        if int(i)!=0:
            r+=int(i)*60

r+=int(t[-1])
r+=int(t[-2])*10
s=k
t=r


if s>=t:
    s-=t

else:
    s+=23*60
    s-=t
a=''
n=s//60
m=s%60
if len(str(n))==1:
    a+='0'
    if n==0:
        a+='0'

    else:
        a+=str(n)

else:
    a+=str(n)        
a+=':'

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

    else:
        a+=str(m)

else:
    a+=str(m)

print(a)

