C# (C Sharp) programming

Что выведет код ?
using System;

using System.Text;

public class Program

    {

        public static void Main(string[] args)

        {

            String str = "";

 

            StringBuilder sb1 = new StringBuilder("TechBeamers");

            StringBuilder sb2 = new StringBuilder("TechBeamers");

            StringBuilder sb3 = new StringBuilder("Welcome");

            StringBuilder sb4 = sb3;

 

            if (sb1.Equals(sb2)) str += "1";

            if (sb2.Equals(sb3)) str += "2";

            if (sb3.Equals(sb4)) str += "3";

 

 

            String str1 = "TechBeamers";

            String str2 = "Welcome";

            String str3 = str2;

 

            if (str1.Equals(str2)) str += "4";

            if (str2.Equals(str3)) str += "5";

            Console.WriteLine(str);

        }

    }
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