import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

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

		int ans = 0;
		if (A - B < C) {
			ans = C - (A - B);
		}
		System.out.println(ans);

	}
} import java.io.FileNotFoundException; FileNotFoundException java.io import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

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

		int ans = 0;
		if (A - B < C) {
			ans = C - (A - B);
		}
		System.out.println(ans);

	}
} Main public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

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

		int ans = 0;
		if (A - B < C) {
			ans = C - (A - B);
		}
		System.out.println(ans);

	} main {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

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

		int ans = 0;
		if (A - B < C) {
			ans = C - (A - B);
		}
		System.out.println(ans);

	} 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 sc.close() sc.close sc int ans = 0; ans 0 if (A - B < C) {
			ans = C - (A - B);
		} A - B < C A - B A B C {
			ans = C - (A - B);
		} ans = C - (A - B) ans C - (A - B) C (A - B) A B System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

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

		int ans = 0;
		if (A - B < C) {
			ans = C - (A - B);
		}
		System.out.println(ans);

	}
} public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

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

		int ans = 0;
		if (A - B < C) {
			ans = C - (A - B);
		}
		System.out.println(ans);

	}
} Main
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

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

		int ans = 0;
		if (A - B < C) {
			ans = C - (A - B);
		}
		System.out.println(ans);

	}
}
