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: Wrong Answer)

fn main() {
    let (a,b,c)
        = {let v: Vec<i32> = read_vec(); (v[0],v[1],v[2])};
    println!("{}",c-(a-b));
}

fn get_line() -> String {
    let mut buf = String::new();
    std::io::stdin().read_line(&mut buf).ok();
    buf.trim().to_owned()
}

fn read<T: std::str::FromStr>() -> T{
    get_line().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T>{
    get_line().split_whitespace()
        .map(|e| e.parse().ok().unwrap()).collect()
}