using System;

public class Program

{

    public static void Main()

    {

        string s1 = "строка";

          System.Text.StringBuilder sb = new 

          System.Text.StringBuilder(s1);

          System.Console.WriteLine(sb);

          string s2 = sb.ToString();

          OpTest<string>(s1, s2);

          OpTest2<string>(s1, s2);

    }

    public static void OpTest<T>(T s, T t) where T : class {

          System.Console.WriteLine(s == t);

        }

    public static void OpTest2<T>(T s, T t) where T : class {

          System.Console.WriteLine(s.Equals(t));

        }

}