using System;

public class Program

{

    public static void Main()

    {

    /*  string hoten,chuoi;

        Console.WriteLine("Nhap ho va ten:");

        hoten = Console.ReadLine();

        string HT = hoten.ToUpper();

        int diem;

        Console.WriteLine("Nhap diem:");

        chuoi = System.Console.ReadLine();

        diem = System.Convert.ToInt32(chuoi);

        Console.WriteLine("Ho va ten: {0}",HT);

        Console.WriteLine("Diem: {0:0}",diem);

        if (diem>=8 && diem <= 10)

        {

            Console.WriteLine("=> Hoc sinh gioi");

        }

        else if (diem < 8 && diem >=5)

        {

            Console.WriteLine("=> Hoc sinh kha");

        }

        else if (diem>0 && diem <5)

        {

            Console.WriteLine("=> Hoc sinh yeu");

        }

        else

        {

            Console.WriteLine("ban da nhap sai");

        }

    */

            Console.Write("Kiem tra so nguyen to trong C#:\n");

            Console.Write("----------------------------");

            Console.Write("\n\n");

​

            int number;

            int bien_dem = 0;

​

            Console.Write("Nhap mot so bat ky: ");

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

​

            for (int i = 1; i <= number; i++)

                if (number % i == 0)

                    bien_dem++;

​

            if (bien_dem == 2)

                Console.WriteLine("So da cho la so nguyen to.");

            else

                Console.WriteLine("So da cho khong phai la so nguyen to.");        

        Console.ReadLine();

    }

}