Problem:
Score : 100 points

Problem Statement

We have a sandglass that runs for X seconds. The sand drops from the upper bulb at a rate of 1 gram per second. That is, the upper bulb initially contains X grams of sand.

How many grams of sand will the upper bulb contains after t seconds?

Constraints

1≤X≤10^9

1≤t≤10^9

X and t are integers.

Input

The input is given from Standard Input in the following format:

X t

Output

Print the number of sand in the upper bulb after t second.

Sample Input 1

100 17

Sample Output 1

83

17 out of the initial 100 grams of sand will be consumed, resulting in 83 grams.

Sample Input 2

48 58

Sample Output 2

0

All 48 grams of sand will be gone, resulting in 0 grams.

Sample Input 3

1000000000 1000000000

Sample Output 3

0

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<iostream>
#include<cstdio>
#include<cstdlib> 
#include<cstring>
using namespace std;
int read()
{
	int x=0,f=1; char c=getchar();
	while (c<'0'||c>'9') {if (c=='-') f=-1; c=getchar();}
	while (c>='0'&&c<='9') {x=x*10+c-'0';c=getchar();}
	return x*f;
}
int x,t,a;
int main()
{
	x=read(); t=read();
	if (x>t) a=x-t; 
	cout<<a;
	return 0;
}