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();
        double kekkai = (Math.sqrt(2)*(Math.sqrt(x*x+y*y)+r));
        if(kekkai%1==0){
          System.out.println((int)kekkai);  
        }else{
            System.out.println((int)Math.ceil(kekkai));
        }
        
    }
}