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.
s1=input()
s2=input()
b=int(s1[3:5])
d=int(s2[3:5])
a=int(s1[0:2])
c=int(s2[0:2])
y=0
x=0
if(b-d<0):
    y=60+b-d
    a=a-1
else:
    y=b-d
if(a-c<0):
    x=24+a-c
else:
    x=a-c
k=''
if(x<10):
    k=k+'0'+str(x)
else:
    k=k+str(x)
k=k+':'
if(y<10):
    k=k+'0'+str(y)
else:
    k=k+str(y)
print(k)