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 (GCC 5.4.1) (judge verdict: Runtime Error)

#include <stdio.h>

int main(void){
  int n; //要素数
  scanf("%d", &n);
  int b[n];//整数列

  int i , ii;//ループ用

  for(i = 0; i < n; i++){
    scanf("%d", &b[i]);
  }//整数列の値を取得

  int max = 0;

  for(i = 0; i < n; i++){
    if(max < b[i]){
      max = b[i];
    }
  }//整数列の最大値を求める

  int countmax = 0, count = 0;

  for(i = 0; i <= max; i++){
    for(ii = 0; ii < n; ii++){
      if((b[ii] == i) || (b[ii] == i + 1) || (b[ii] == i - 1)){
        count++;
      }
    }

    if(count > countmax){
      countmax = count;
    }

    count = 0;
  }//ここではXを0から1ずつ増やして調べる

  printf("%d", countmax);
}