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.
while True:
    current = input().split(":")
    duration = input().split(":")
    if len(current) == 2 and len(duration) == 2:
        break

jam = 0
menit = 0

jam = int(current[0]) - int(duration[0])
menit = int(current[1]) - int(duration[1])

if jam < 0:
    jam = 24 - jam
    
if menit < 0:
    menit = 60 - menit
    
if 0 <= jam < 10:
    jam = "0" + str(jam)

if 0 <= menit < 10:
    menit = "0" + str(menit)
    
print(str(jam) + ":" + str(menit))