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.
time1 = [int(x) for x in input().split(':')]
time2 = input().split(':')
time2 = 60 * int(time2[0]) + int(time2[1])

for i in range(time2):
    time1[1] -= 1
    time1[1] %= 60
    if time1[1] % 60 == 0:
        time1[0] -= 1
        time1[0] %= 24

#print(time1)

if len(str(time1[0])) == 1 and len(str(time1[1])) == 1:
    print('0' + str(time1[0]) + ':' + '0' + str(time1[1]))
elif len(str(time1[0])) == 1:
    print('0' + str(time1[0]) + ':' + str(time1[1]))
elif len(str(time1[1])) == 1:
    print(str(time1[0]) + ':' + '0' + str(time1[1])) 
else:
    print(str(time1[0]) + ':' + str(time1[1]))