import java.util.Random;
import java.util.Scanner;

public class Main {
    public static void main(String[] args){

      Scanner sc = new Scanner(System.in);
        int A = sc.nextInt();
        int B = sc.nextInt();

        int differnce = A-B;

        int C = sc.nextInt();

        if (C > differnce) {
            System.out.println(C-differnce);
        } else {
            System.out.println(0);
        }

    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz