import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import static java.lang.System.in;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String[] inputs = reader.readLine().split(" ");
        int x = Integer.parseInt(inputs[0]);
        int y = Integer.parseInt(inputs[1]);
        int r = Integer.parseInt(inputs[2]);
        x = Math.abs(x);
        y = Math.abs(y);
        System.out.println((int)Math.ceil(x + y + r * Math.sqrt(2)));
    }

}