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.
from math import *
from collections import deque
from copy import deepcopy
import sys
def inp(): return sys.stdin.readline().rstrip("\r\n") #for fast input
def multi(): return map(int,input().split())
def lis(): return list(map(int, inp().split()))
def out(var): sys.stdout.write(str(var))  #for fast output, always take string
def printlist(a) :
    for p in range(0,len(a)):
        out(str(a[p]) + ' ')

def isPrime(n) :
    if (n <= 1) : return False
    if (n <= 3) : return True
    if (n % 2 == 0 or n % 3 == 0) : return False
    i = 5
    while(i * i <= n) :
        if (n % i == 0 or n % (i + 2) == 0) :
            return False
        i = i + 6
    return True

#copied functions end

#start coding

a=str(inp())
b=str(inp())
hr=0
mini=0
# print(int(a[3:5])-int(b[3:5]))
if(int(a[3:5])>=int(b[3:5])):
    mini=int(a[3:5])-int(b[3:5])
else:
    mini = 60-abs(int(a[3:5]) - int(b[3:5]))

if(int(a[0:2])>=int(b[0:2])):
    hr=int(a[0:2])-int(b[0:2])
else:
    hr = 24-abs(int(a[0:2]) - int(b[0:2]))

if(int(hr)<10):
    print("0"+str(hr),end="")
else:
    print(str(hr),end="")
print(":",end="")
if(mini<10):
    print("0"+str(mini),end="")
else:
    print(str(mini))
# print(str(hr)+":"+str(mini))