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.
# your code goes here
s=input()
t=input()
s=s.split(':')
t=t.split(':')
#print(s,t)
h1=int(s[0])
h2=int(t[0])
m1=int(s[1])
m2=int(t[1])
#print(h1,h2,m1,m2)
if(m1<m2):
    h2=h2+1
    m1=m1+60
m1=m1-m2
if h1<h2:
    h1=h1+24
h1=h1-h2
h1=str(h1)
m1=str(m1)

if(len(h1)==1):
    h1='0'+h1;
if(len(m1)==1):
    m1='0'+m1;

print(h1,end="")
print(":",end="")
print(m1)