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 c = sc.nextInt();

		int box1 = a - b;
		int d = c - box1;

		if (box1 > c) {
			System.out.println("0");
		} else {
			System.out.println(d);
		}
		sc.close();
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();

		int box1 = a - b;
		int d = c - box1;

		if (box1 > c) {
			System.out.println("0");
		} else {
			System.out.println(d);
		}
		sc.close();
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();

		int box1 = a - b;
		int d = c - box1;

		if (box1 > c) {
			System.out.println("0");
		} else {
			System.out.println(d);
		}
		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);

		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();

		int box1 = a - b;
		int d = c - box1;

		if (box1 > c) {
			System.out.println("0");
		} else {
			System.out.println(d);
		}
		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc int c = sc.nextInt(); c sc.nextInt() sc.nextInt sc int box1 = a - b; box1 a - b a b int d = c - box1; d c - box1 c box1 if (box1 > c) {
			System.out.println("0");
		} else {
			System.out.println(d);
		} box1 > c box1 c {
			System.out.println("0");
		} System.out.println("0") System.out.println System.out System System.out "0" {
			System.out.println(d);
		} System.out.println(d) System.out.println System.out System System.out d sc.close() sc.close sc String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();

		int box1 = a - b;
		int d = c - box1;

		if (box1 > c) {
			System.out.println("0");
		} else {
			System.out.println(d);
		}
		sc.close();
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();

		int box1 = a - b;
		int d = c - box1;

		if (box1 > c) {
			System.out.println("0");
		} else {
			System.out.println(d);
		}
		sc.close();
	}
} Main
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 c = sc.nextInt();

		int box1 = a - b;
		int d = c - box1;

		if (box1 > c) {
			System.out.println("0");
		} else {
			System.out.println(d);
		}
		sc.close();
	}
}