import java.util.*;
import static java.lang.System.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		int x = sc.nextInt();
		int y = sc.nextInt();
		int r = sc.nextInt();
		double ans = Math.sqrt(2);
		ans *= r;
		ans += Math.abs(x)+Math.abs(y);
		out.println((int)Math.ceil(ans));
	}
}