import java.util.*;

public class Main {
	public static void main(String[] args) {
		// practice contest

		Scanner sc = new Scanner(System.in);

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

		int x = a - b;
		if (x <= c) {
			System.out.println(c - x);
		}
		if (x > c) {
			System.out.println(0);
		}
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
		// practice contest

		Scanner sc = new Scanner(System.in);

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

		int x = a - b;
		if (x <= c) {
			System.out.println(c - x);
		}
		if (x > c) {
			System.out.println(0);
		}
	}
} Main public static void main(String[] args) {
		// practice contest

		Scanner sc = new Scanner(System.in);

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

		int x = a - b;
		if (x <= c) {
			System.out.println(c - x);
		}
		if (x > c) {
			System.out.println(0);
		}
	} main {
		// practice contest

		Scanner sc = new Scanner(System.in);

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

		int x = a - b;
		if (x <= c) {
			System.out.println(c - x);
		}
		if (x > c) {
			System.out.println(0);
		}
	} 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 x = a - b; x a - b a b if (x <= c) {
			System.out.println(c - x);
		} x <= c x c {
			System.out.println(c - x);
		} System.out.println(c - x) System.out.println System.out System System.out c - x c x if (x > c) {
			System.out.println(0);
		} x > c x c {
			System.out.println(0);
		} System.out.println(0) System.out.println System.out System System.out 0 String[] args args public class Main {
	public static void main(String[] args) {
		// practice contest

		Scanner sc = new Scanner(System.in);

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

		int x = a - b;
		if (x <= c) {
			System.out.println(c - x);
		}
		if (x > c) {
			System.out.println(0);
		}
	}
} public class Main {
	public static void main(String[] args) {
		// practice contest

		Scanner sc = new Scanner(System.in);

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

		int x = a - b;
		if (x <= c) {
			System.out.println(c - x);
		}
		if (x > c) {
			System.out.println(0);
		}
	}
} Main
import java.util.*;

public class Main {
	public static void main(String[] args) {
		// practice contest

		Scanner sc = new Scanner(System.in);

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

		int x = a - b;
		if (x <= c) {
			System.out.println(c - x);
		}
		if (x > c) {
			System.out.println(0);
		}
	}
}
