import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        String[] params = in.nextLine().split(" ");
        int a = Integer.parseInt(params[0]);
        int b = Integer.parseInt(params[1]);
        int c = Integer.parseInt(params[2]);

        if( a < b + c ){
            System.out.println( c - a + b );
        }
        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