import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);
		
		int a = scan.nextInt();
		int b = scan.nextInt();
		int c = scan.nextInt();
		int z = 0;
		
		if (a-b >= c ) {
			z = 0;
		} else {
			z = c - (a-b);
		}
      
		System.out.println(z);
	}

}

/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