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

def input():    return sys.stdin.readline().strip()
def iinput():   return int(input())
def rinput():   return map(int, sys.stdin.readline().strip().split()) 
def get_list(): return list(map(int, sys.stdin.readline().strip().split())) 


s=input().split(":")
t=input().split(":")

p=int(s[0])-int(t[0])

if(p<0):
    p+=24
p=str(p)

if(len(str(p))!=2):
    p=str('0')+p

p1=int(s[1])-int(t[1])


if(p1<0):
    p1+=60
p1=str(p1)

if(len(str(p1))!=2):
    p1=str('0')+p1

print(p+":"+p1)
