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)

fn main() {
    let mode = "a";
    if mode == "a" {
        a::solve();
    }
}

mod a {
    use std;
    use std::io::Read;

    pub fn solve() {
        let mut buf = String::new();
        std::io::stdin().read_to_string(&mut buf).unwrap();
        let mut text = buf.split_whitespace();
        let a = text.next().unwrap().parse().unwrap();
        let b = text.next().unwrap().parse().unwrap();
        let c = text.next().unwrap().parse().unwrap();

        let res = calc(a, b, c);
        println!("{}", res);
    }

    fn calc(a: i32, b: i32, c: i32) -> i32 {
        let used = std::cmp::min(a - b, c);
        c - used
    }

    #[cfg(test)]
    mod tests {
        #[test]
        fn test1() {}
    }

}