import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner stdIn=new Scanner(System.in);
		int a=stdIn.nextInt();
		int b=stdIn.nextInt();
		int c=stdIn.nextInt();
		int x=b+c;
		if(a<x)
			System.out.println(x-a);
		else
			System.out.println("0");

	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner stdIn=new Scanner(System.in);
		int a=stdIn.nextInt();
		int b=stdIn.nextInt();
		int c=stdIn.nextInt();
		int x=b+c;
		if(a<x)
			System.out.println(x-a);
		else
			System.out.println("0");

	}

} Main public static void main(String[] args) {
		Scanner stdIn=new Scanner(System.in);
		int a=stdIn.nextInt();
		int b=stdIn.nextInt();
		int c=stdIn.nextInt();
		int x=b+c;
		if(a<x)
			System.out.println(x-a);
		else
			System.out.println("0");

	} main {
		Scanner stdIn=new Scanner(System.in);
		int a=stdIn.nextInt();
		int b=stdIn.nextInt();
		int c=stdIn.nextInt();
		int x=b+c;
		if(a<x)
			System.out.println(x-a);
		else
			System.out.println("0");

	} Scanner stdIn=new Scanner(System.in); stdIn new Scanner(System.in) int a=stdIn.nextInt(); a stdIn.nextInt() stdIn.nextInt stdIn int b=stdIn.nextInt(); b stdIn.nextInt() stdIn.nextInt stdIn int c=stdIn.nextInt(); c stdIn.nextInt() stdIn.nextInt stdIn int x=b+c; x b+c b c if(a<x)
			System.out.println(x-a);
		else
			System.out.println("0"); a<x a x System.out.println(x-a) System.out.println System.out System System.out x-a x a 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) {
		Scanner stdIn=new Scanner(System.in);
		int a=stdIn.nextInt();
		int b=stdIn.nextInt();
		int c=stdIn.nextInt();
		int x=b+c;
		if(a<x)
			System.out.println(x-a);
		else
			System.out.println("0");

	}

} public class Main {

	public static void main(String[] args) {
		Scanner stdIn=new Scanner(System.in);
		int a=stdIn.nextInt();
		int b=stdIn.nextInt();
		int c=stdIn.nextInt();
		int x=b+c;
		if(a<x)
			System.out.println(x-a);
		else
			System.out.println("0");

	}

} Main
import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner stdIn=new Scanner(System.in);
		int a=stdIn.nextInt();
		int b=stdIn.nextInt();
		int c=stdIn.nextInt();
		int x=b+c;
		if(a<x)
			System.out.println(x-a);
		else
			System.out.println("0");

	}

}
