import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int a = in.nextInt();
		int b = in.nextInt();
		int c = in.nextInt();
		System.out.println(solve(a, b, c));
		in.close();
	}

	private static int solve(int a, int b, int c) {
		a = a - b;
		if (a >= c)
			return 0;
		else
			return c - a;
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int a = in.nextInt();
		int b = in.nextInt();
		int c = in.nextInt();
		System.out.println(solve(a, b, c));
		in.close();
	}

	private static int solve(int a, int b, int c) {
		a = a - b;
		if (a >= c)
			return 0;
		else
			return c - a;
	}
} Main public static void main(String[] args) {
		Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int a = in.nextInt();
		int b = in.nextInt();
		int c = in.nextInt();
		System.out.println(solve(a, b, c));
		in.close();
	} main {
		Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int a = in.nextInt();
		int b = in.nextInt();
		int c = in.nextInt();
		System.out.println(solve(a, b, c));
		in.close();
	} Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in))); in new Scanner(new BufferedReader(new InputStreamReader(System.in))) int a = in.nextInt(); a in.nextInt() in.nextInt in int b = in.nextInt(); b in.nextInt() in.nextInt in int c = in.nextInt(); c in.nextInt() in.nextInt in System.out.println(solve(a, b, c)) System.out.println System.out System System.out solve(a, b, c) solve a b c in.close() in.close in String[] args args private static int solve(int a, int b, int c) {
		a = a - b;
		if (a >= c)
			return 0;
		else
			return c - a;
	} solve {
		a = a - b;
		if (a >= c)
			return 0;
		else
			return c - a;
	} a = a - b a a - b a b if (a >= c)
			return 0;
		else
			return c - a; a >= c a c return 0; 0 return c - a; c - a c a int a a int b b int c c public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int a = in.nextInt();
		int b = in.nextInt();
		int c = in.nextInt();
		System.out.println(solve(a, b, c));
		in.close();
	}

	private static int solve(int a, int b, int c) {
		a = a - b;
		if (a >= c)
			return 0;
		else
			return c - a;
	}
} public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int a = in.nextInt();
		int b = in.nextInt();
		int c = in.nextInt();
		System.out.println(solve(a, b, c));
		in.close();
	}

	private static int solve(int a, int b, int c) {
		a = a - b;
		if (a >= c)
			return 0;
		else
			return c - a;
	}
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int a = in.nextInt();
		int b = in.nextInt();
		int c = in.nextInt();
		System.out.println(solve(a, b, c));
		in.close();
	}

	private static int solve(int a, int b, int c) {
		a = a - b;
		if (a >= c)
			return 0;
		else
			return c - a;
	}
}