using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Nhap N:");

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

        int i=2;

        int dem=0;

        while(i<=N/2)

            {if(N%i==0)

                {dem=dem+1;}

            i++;

            }

        if(dem==0)

            {Console.WriteLine("so {0} la so nguyen to",N);}

        else

            {Console.WriteLine("so {0} khong phai la so nguyen to",N);}

    }

}