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.
wake_up_time = input().split(':')
sleep_duration = input().split(':')

wake_up_time = 60 * int(wake_up_time[0]) + int(wake_up_time[1])
sleep_duration = 60 * int(sleep_duration[0]) + int(sleep_duration[1])

bed_time = wake_up_time - sleep_duration

if bed_time < 0:
    bed_time += 24 * 60

print('{:0>2d}:{:0>2d}'.format(*divmod(bed_time, 60)))

