using System;

using System.Linq;

using Novell.Directory.Ldap.Utilclass;

public class Program

{

    public static void Main()

    {

        const string DistinguishedName = "CN=r1,OU=DN1";

        Dn dn = new Dn(DistinguishedName);

        string commonName = dn.RdNs.FirstOrDefault(x => x.Type == "CN")?.Value;

        Console.WriteLine("DN: {0}, CN: {1}", DistinguishedName, commonName);

    }

}