import java.util.Scanner;

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