using System;

public class Program

{

    public static void Main()

    {

         int n;

            int sum = 0;

            Console.Write("Nhap vao n: ");

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

            while (n != 0)

            {

                sum += n % 10;

                n = n / 10;

            };

            Console.WriteLine($"Tong cac chu so la {sum}");

            Console.ReadLine();

    }

}