using System;

using System.Text;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

​

        String string1 = "One";

        String string2 = "One";

        StringBuilder stringBuilder1 = new StringBuilder("One");

        StringBuilder stringBuilder2 = new StringBuilder("One");

        List<Object> list = new List<Object>();

        list.Add(string1);

        list.Add(stringBuilder1);

        Console.WriteLine(list.Contains(string2));

        Console.WriteLine(list.Contains(stringBuilder2));

        Console.WriteLine(list.Contains(stringBuilder2.ToString()));

    }

}