using System;

public class Program

{

    public static void Main()

    {

        int ctr = 0;

        int i = 2;

        Console.WriteLine("Please enter a number (Number > 0):");

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

        Console.WriteLine("-----------------------------------");

        while(i <= num/2)

        {

            if(num % i == 0)

            {

                ctr++;

                break; //чупи do...while-а

            }

            i++;

        }

        if(num <= 0)

        {

            Console.WriteLine("Wrong!!!");

        }

        else

        {

            if(ctr == 0 && num != 1)

            {

                Console.WriteLine("{0} is a prime number.",num);

            }

            else

            {

                Console.WriteLine("{0} is NOT a prime number.",num);

            }

        }   

    }

}