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 <cstring>
#include <algorithm>
#include <queue>
#include <stack>
#include <cmath>
#include <vector>
#include<functional>  
#define ll long long
#define out(a) printf("%d",a)
using namespace std;
int n;
int a,b;
int read()
{
	int s=0,t=1; char ch;
	while (ch<'0'||ch>'9') {if (ch=='-') t=-1;ch=getchar();}
	while (ch>='0'&&ch<='9') {s=s*10+ch-'0';ch=getchar();}
	return s*t;
}
int main()
{
	a=read(); b=read();
	if (a>=b) out(a-b);
	else out(0);
}