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.
h_1, m_1  = map(int, input().split(':'))
h_2, m_2  = map(int, input().split(':'))

cur_time = h_1 * 60 + m_1
sleep_time = h_2 * 60 + m_2

result_time = 1440 + cur_time - sleep_time if cur_time - sleep_time < 0 else cur_time - sleep_time

result_h = '0' + str(result_time // 60) if result_time // 60 < 10 else str(result_time // 60)
result_m = '0' + str(result_time % 60) if result_time % 60 < 10 else str(result_time % 60)

print( f'{result_h}:{result_m}' )