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 Rust (1.15.1) (judge verdict: Accepted)

use std::io::Read;
use std::cmp;

fn main() {
    let mut buf = String::new();

    // 標準入力から全部bufに読み込む
    std::io::stdin().read_to_string(&mut buf);

    // 読み込んだStringを空白で分解する
    let mut iter = buf.split_whitespace();

    // aの読み込み
    let a: i32 = iter.next().unwrap().parse().unwrap();
    // bの読み込み
    let b: i32 = iter.next().unwrap().parse().unwrap();
    // cの読み込み
    let c: i32 = iter.next().unwrap().parse().unwrap();

    // 容器2に残る水の量
    let x: i32 = c - (a - b);

    if x <= 0 {
        println!("{}", 0);
    } else {
        println!("{}", x);
    }
}