import java.util.Scanner;

class Main {

    public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);

	int A, B, C;
	A = sc.nextInt();
	B = sc.nextInt();
	C = sc.nextInt();

	int ans = -1 * (A - B - C);
	if (ans > 0)
	    System.out.println(ans);
	else
	    System.out.println(0);
    }
} import java.util.Scanner; Scanner java.util class Main {

    public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);

	int A, B, C;
	A = sc.nextInt();
	B = sc.nextInt();
	C = sc.nextInt();

	int ans = -1 * (A - B - C);
	if (ans > 0)
	    System.out.println(ans);
	else
	    System.out.println(0);
    }
} Main public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);

	int A, B, C;
	A = sc.nextInt();
	B = sc.nextInt();
	C = sc.nextInt();

	int ans = -1 * (A - B - C);
	if (ans > 0)
	    System.out.println(ans);
	else
	    System.out.println(0);
    } main {
	Scanner sc = new Scanner(System.in);

	int A, B, C;
	A = sc.nextInt();
	B = sc.nextInt();
	C = sc.nextInt();

	int ans = -1 * (A - B - C);
	if (ans > 0)
	    System.out.println(ans);
	else
	    System.out.println(0);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int A A B B C; C A = sc.nextInt() A sc.nextInt() sc.nextInt sc B = sc.nextInt() B sc.nextInt() sc.nextInt sc C = sc.nextInt() C sc.nextInt() sc.nextInt sc int ans = -1 * (A - B - C); ans -1 * (A - B - C) -1 1 (A - B - C) A - B - C A B C if (ans > 0)
	    System.out.println(ans);
	else
	    System.out.println(0); ans > 0 ans 0 System.out.println(ans) System.out.println System.out System System.out ans System.out.println(0) System.out.println System.out System System.out 0 String[] args args
import java.util.Scanner;

class Main {

    public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);

	int A, B, C;
	A = sc.nextInt();
	B = sc.nextInt();
	C = sc.nextInt();

	int ans = -1 * (A - B - C);
	if (ans > 0)
	    System.out.println(ans);
	else
	    System.out.println(0);
    }
}