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.
class Time:
	def __init__(self, hh, mm):
		self.h = hh
		self.m = mm
	
	def __sub__(self, other):
		res_h = (self.h-other.h) % 24
		res_m = (self.m-other.m) % 60
		if self.m-other.m < 0:
			res_h = (res_h-1) % 24
		return Time(res_h, res_m)
	
	def __str__(self):
		return '{}:{}'.format(str(self.h).zfill(2), str(self.m).zfill(2))

cur_time = Time(*list(map(int, input().split(':'))))
sleep_time = Time(*list(map(int, input().split(':'))))
print(cur_time-sleep_time)
