using System;

public class Program

{

    public static void Main()

    {

                Console.WriteLine("nhap so n");

                int n = Convert.ToInt32(Console.ReadLine());

                int sum = 0, conlai;

                if (n <= 0)

                    Console.WriteLine("moi cac ban nhap lai so");

                else

                {

                    while (n >= 1)

                    {

                        conlai = n % 10;

                        n = n / 10;

                        if (conlai % 2 == 0)

                            sum = sum + conlai;

                    }

​

​

                Console.WriteLine($"tong cac chu so chan cua {n} la {sum}");

                }

                Console.ReadKey();

​

    }

}