import java.util.*;

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