//----- Daniel Donchev ----- .NET 7 ----- for educational purposes

using System;

public class Program

{

    public static void Main() // example 2

    {

        int val= 7;

        string str= "";

        for(int i=2; i < Math.Sqrt(val); i++)

        {   if(val % i == 0)

            {   str= "not "; break;

            }

        }

        Console.WriteLine($"{val} is {str}prime");

    }

}