using System;

public class Program

{

    public static void Main()

    {

         // Garaas ogson toonii tsifruudiin niilber olno

            int a, y, z;

            Console.Write("a=");

            a = Convert.ToInt32(Console.ReadLine());

            y = 0;

​

            for  (z=0;a>z;a=a/10)

            {

                y = y + a % 10;

            }

            Console.Write(y);

            Console.ReadLine();

    }

}