import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int x = scan.nextInt();
		int y = scan.nextInt();
		int r = scan.nextInt();
		scan.close();
		if(x < 0) {
			x = - x;
		}
		if(y < 0) {
			y = - y;
		}
		int k = x + y + (int)(Math.sqrt(2) * r) + 1;


		System.out.println(k);
	}
}