using System;

public class Program

{

    public static void Main()

    {

        int i, count = 0, n;

        Console.Write("Enter a number:");

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

        for (i=1;i<=n;i++)

        {

            if(n%i==0)

            {

            count++;    

            }

        }

        if(count==2)

        {

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

        }

        else 

        {

        Console.WriteLine ("{0} is not a prime number",n);  

        }

    }

}