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 = str(input())
t = str(input())

c = int(s[0:2])*60 + int(s[3:5]) - int(t[0:2])*60 - int(t[3:5])
if(c<0):
    c += 1440
hours = c//60
minutes = c%60

if(hours<10):
    p = '0' + str(hours) + ':'
else:
    p = str(hours) + ':'

if(minutes<10):
    p = p + '0' + str(minutes)
else:
    p = p + str(minutes)
print(p)