/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner sc = new Scanner(System.in);
		
		final int x = sc.nextInt();
		final int y = sc.nextInt();
		final int r = sc.nextInt();
		
		System.out.println((int) (Math.abs(x) + Math.abs(y) + Math.ceil(r * Math.sqrt(2))));
	}
}