using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var joinerBoltons = new string[] { "1", "2", "3", "4", "5" };

        var packageBoltons = new string[] { "1", "2", "3" };

        var validBoltons = packageBoltons.IntersectBy(joinerBoltons, boltOn => boltOn);

        Console.WriteLine(string.Join(", ", validBoltons));

    }

}