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.
import os
line_number = 1
current_working_dir = os.getcwd()
my_local_machine = current_working_dir.find('rachel')
# print(my_local_machine)

def myinput():
    global line_number, lines, my_local_machine
    if line_number == 1:
        lines = lines.split('\n')

    # print(len(lines))
    if my_local_machine > 0:
        line = lines[line_number]
    else:
        line = input()
    
    line_number += 1
    return(line)

lines = '''
00:00
01:00
'''
import datetime 

start = myinput() 
l = myinput() 
start_hour = int(start[0:2])
start_minute = int(start[3:])
length = int(l[0:2]) * 60 + int(l[3:])

start = datetime.datetime(100, 1, 1, start_hour, start_minute, 0)
end = start - datetime.timedelta(minutes=length)
result = str(end.time())
print(result[:5])