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);
	}

} import java.util.Scanner; Scanner java.util 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);
	}

} 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);
	} main {

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

} 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);
	}

} Main
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);
	}

}
