using System;

public class Program

{

    public static void Main()

    {

        int num, x = 2;

        Console.WriteLine("please enter number:");

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

        bool isprime=true;

            while (num/2 >= x && isprime)

            {

                if (num % x == 0)

                    isprime=false;

                    x++;

            }

            if(isprime)

            Console.WriteLine("The number you enter is  a prime number.:");

            else

            Console.WriteLine("The number you enter is not a prime number.:");

        }

}