import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String args[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str[] = br.readLine().split(" ");
		int a = Integer.parseInt(str[0]);
		int b = Integer.parseInt(str[1]);
		int c = Integer.parseInt(str[2]);

		int d = a - b - c;
		if (d < 0) {
			System.out.println(Math.abs(d));
		} else {
			System.out.println(0);
		}
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
	public static void main(String args[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str[] = br.readLine().split(" ");
		int a = Integer.parseInt(str[0]);
		int b = Integer.parseInt(str[1]);
		int c = Integer.parseInt(str[2]);

		int d = a - b - c;
		if (d < 0) {
			System.out.println(Math.abs(d));
		} else {
			System.out.println(0);
		}
	}
} Main public static void main(String args[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str[] = br.readLine().split(" ");
		int a = Integer.parseInt(str[0]);
		int b = Integer.parseInt(str[1]);
		int c = Integer.parseInt(str[2]);

		int d = a - b - c;
		if (d < 0) {
			System.out.println(Math.abs(d));
		} else {
			System.out.println(0);
		}
	} main {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str[] = br.readLine().split(" ");
		int a = Integer.parseInt(str[0]);
		int b = Integer.parseInt(str[1]);
		int c = Integer.parseInt(str[2]);

		int d = a - b - c;
		if (d < 0) {
			System.out.println(Math.abs(d));
		} else {
			System.out.println(0);
		}
	} BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) String str[] = br.readLine().split(" "); str br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int a = Integer.parseInt(str[0]); a Integer.parseInt(str[0]) Integer.parseInt Integer str[0] str 0 int b = Integer.parseInt(str[1]); b Integer.parseInt(str[1]) Integer.parseInt Integer str[1] str 1 int c = Integer.parseInt(str[2]); c Integer.parseInt(str[2]) Integer.parseInt Integer str[2] str 2 int d = a - b - c; d a - b - c a - b - c a b c if (d < 0) {
			System.out.println(Math.abs(d));
		} else {
			System.out.println(0);
		} d < 0 d 0 {
			System.out.println(Math.abs(d));
		} System.out.println(Math.abs(d)) System.out.println System.out System System.out Math.abs(d) Math.abs Math d {
			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[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str[] = br.readLine().split(" ");
		int a = Integer.parseInt(str[0]);
		int b = Integer.parseInt(str[1]);
		int c = Integer.parseInt(str[2]);

		int d = a - b - c;
		if (d < 0) {
			System.out.println(Math.abs(d));
		} else {
			System.out.println(0);
		}
	}
} public class Main {
	public static void main(String args[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str[] = br.readLine().split(" ");
		int a = Integer.parseInt(str[0]);
		int b = Integer.parseInt(str[1]);
		int c = Integer.parseInt(str[2]);

		int d = a - b - c;
		if (d < 0) {
			System.out.println(Math.abs(d));
		} else {
			System.out.println(0);
		}
	}
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String args[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str[] = br.readLine().split(" ");
		int a = Integer.parseInt(str[0]);
		int b = Integer.parseInt(str[1]);
		int c = Integer.parseInt(str[2]);

		int d = a - b - c;
		if (d < 0) {
			System.out.println(Math.abs(d));
		} else {
			System.out.println(0);
		}
	}
}