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 sys
import math

sh, sm = [int(x) for x in (sys.stdin.readline()).split(":")]
th, tm = [int(x) for x in (sys.stdin.readline()).split(":")]

rm = sm - tm
if(rm < 0):
    th += 1
    rm = 60 + rm
    
rh = sh - th
if(rh < 0):
    rh = 24 + rh
    
outrh = ""
if(rh < 10):
    outrh = "0" + str(rh)
else:
    outrh = str(rh)

outrm = ""
if(rm < 10):
    outrm = "0" + str(rm)
else:
    outrm = str(rm)
    
print(outrh + ":" + outrm)