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()

if int(s[0]) == 0 & int(s[1]) == 0:
    hour1 = 24

if int(t[0]) == 0 & int(t[1]) == 0:
    hour2 = 24

else:
    hour1 = int(s[:2]) % 12
    hour2 = int(t[:2]) % 12
    hour1 += 12
    hour2 += 12


minutes1 = int(s[3:5])
minutes2 = int(t[3:5])
hour = hour1 - hour2
minutes = minutes1 - minutes2
print("{:02}:{:02}".format(hour, minutes))