Problem:
Score : 100 points

Problem Statement

We have two bottles for holding water.

Bottle 1 can hold up to A milliliters of water, and now it contains B milliliters of water.

Bottle 2 contains C milliliters of water.

We will transfer water from Bottle 2 to Bottle 1 as much as possible.

How much amount of water will remain in Bottle 2?

Constraints

All values in input are integers.

1 \leq B \leq A \leq 20

1 \leq C \leq 20

Input

Input is given from Standard Input in the following format:

A B C

Output

Print the integer representing the amount of water, in milliliters, that will remain in Bottle 2.

Sample Input 1

6 4 3

Sample Output 1

1

We will transfer two milliliters of water from Bottle 2 to Bottle 1, and one milliliter of water will remain in Bottle 2.

Sample Input 2

8 3 9

Sample Output 2

4

Sample Input 3

12 3 7

Sample Output 3

0

Solution in PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php

function calcRemain($A,$B,$C){
  // 容器1
  $youki1 = $A;
  $youki2 = $C;
  
  $youki1_remain = $youki1-$B;
  
  $result = 0;
  if($youki1_remain <= $C) {
      $result = $C-$youki1_remain;

  }else{
      $result = $youki2-$C;

  }
  
  return $result;
}

echo calcRemain($argv[1],$argv[2],$argv[3])."\n";