Properties/Constructor C#

using System;
public class addd
{
    private string boyfriend;
    private string girlfriend;

    public addd() // constructor
    {
        boyfriend ="Omi ";
        girlfriend =  "Riya";
    }

    public string BF { //properties
         get {
            return boyfriend;
         }
         set {
            boyfriend = value;
         }
      }



    public void ad()
    {
        Console.WriteLine(boyfriend+ girlfriend);
    }

}

public class Program
{
    public static void Main()
    {
        Console.WriteLine("Hello World");

        addd obj = new addd();

        obj.ad();
        obj.BF= "Ishmam "; //properties
        obj.ad();
    }
}