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