using System;

public class Program

{

    public static void Main()

    {

        int n;

        Console.Write("Въведи n:");

        n = int.Parse(Console.ReadLine());

        int a = n/100;

        int b = n/10%10;

        int c = n%10;

        int k = a+b;

        int m = b+c;

        if ((a!=0)&&(b!=0)&&(c!=0))

        {

        if (n%b==0)

        {

        Console.WriteLine(k);

        }

        else

        {

        Console.WriteLine(m);

       }

        }

        else

        {

        Console.WriteLine("Грешка");

        }

    }

}