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

public class Main {

	public static void main(String[] args) {
		Scanner reader = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int A, B, C, mili=0;
		A = reader.nextInt();
		B = reader.nextInt();
		C = reader.nextInt();
		mili = (B+C)-A;
		if(mili>0) {
			System.out.println(mili);
		}else {
			System.out.println(0);
		}
	}

} 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 reader = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int A, B, C, mili=0;
		A = reader.nextInt();
		B = reader.nextInt();
		C = reader.nextInt();
		mili = (B+C)-A;
		if(mili>0) {
			System.out.println(mili);
		}else {
			System.out.println(0);
		}
	}

} Main public static void main(String[] args) {
		Scanner reader = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int A, B, C, mili=0;
		A = reader.nextInt();
		B = reader.nextInt();
		C = reader.nextInt();
		mili = (B+C)-A;
		if(mili>0) {
			System.out.println(mili);
		}else {
			System.out.println(0);
		}
	} main {
		Scanner reader = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int A, B, C, mili=0;
		A = reader.nextInt();
		B = reader.nextInt();
		C = reader.nextInt();
		mili = (B+C)-A;
		if(mili>0) {
			System.out.println(mili);
		}else {
			System.out.println(0);
		}
	} Scanner reader = new Scanner(new BufferedReader(new InputStreamReader(System.in))); reader new Scanner(new BufferedReader(new InputStreamReader(System.in))) int A A B B C C mili=0; mili 0 A = reader.nextInt() A reader.nextInt() reader.nextInt reader B = reader.nextInt() B reader.nextInt() reader.nextInt reader C = reader.nextInt() C reader.nextInt() reader.nextInt reader mili = (B+C)-A mili (B+C)-A (B+C) B C A if(mili>0) {
			System.out.println(mili);
		}else {
			System.out.println(0);
		} mili>0 mili 0 {
			System.out.println(mili);
		} System.out.println(mili) System.out.println System.out System System.out mili {
			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) {
		Scanner reader = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int A, B, C, mili=0;
		A = reader.nextInt();
		B = reader.nextInt();
		C = reader.nextInt();
		mili = (B+C)-A;
		if(mili>0) {
			System.out.println(mili);
		}else {
			System.out.println(0);
		}
	}

} public class Main {

	public static void main(String[] args) {
		Scanner reader = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int A, B, C, mili=0;
		A = reader.nextInt();
		B = reader.nextInt();
		C = reader.nextInt();
		mili = (B+C)-A;
		if(mili>0) {
			System.out.println(mili);
		}else {
			System.out.println(0);
		}
	}

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

public class Main {

	public static void main(String[] args) {
		Scanner reader = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
		int A, B, C, mili=0;
		A = reader.nextInt();
		B = reader.nextInt();
		C = reader.nextInt();
		mili = (B+C)-A;
		if(mili>0) {
			System.out.println(mili);
		}else {
			System.out.println(0);
		}
	}

}
