Boolean expresion reducer C#

using System;
using System.Diagnostics;
using System.Net.Sockets;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.IO;
using System.ComponentModel;
using System.Reflection;
using System.Xml;
using System.Globalization;

namespace Program
{
    public class MainClass
    {
        static void Main(string[] args)
        {
            Console.WriteLine(BoolExpressionReducer("t&!(f|f|t&t)") == "t");
            Console.ReadLine();
        }

        private static string BoolExpressionReducer(string Source)
        {
            while (Source.Contains('('))
            {
                int StartSubExpression = 0;
                int EndSubExpression = 0;
                int DeltaSubs = 0;

                for (int i = 0; i < Source.Length; i++)
                {
                    if (Source[i] == '(')
                    {
                        DeltaSubs++;

                        if (StartSubExpression == 0)
                        {
                            StartSubExpression = i + 1;
                        }
                    }
                    else if (Source[i] == ')')
                    {
                        DeltaSubs--;

                        if (DeltaSubs == 0)
                        {
                            EndSubExpression = i - 1;
                            break;
                        }
                    }
                }

                Source = Source.Replace(Source.Substring(StartSubExpression - 1, EndSubExpression - StartSubExpression + 3), BoolExpressionReducer(Source.Substring(StartSubExpression, EndSubExpression - StartSubExpression + 1)));
            }

            while (Source.Contains('!'))
            {
                Source = Source.Replace("!t", "f").Replace("!f", "t");
            }

            while (Source.Count(x => x == '&' || x == '|') > 1)
            {
                if (Source.Contains('&'))
                {
                    int AndIndex = Source.IndexOf('&');
                    string AndString = Source.Substring(AndIndex - 1, 3);

                    Source = Source.Replace(AndString, BoolExpressionReducer(AndString));
                }
                else // Everything is 'or'
                {
                    return Source.Contains('t') ? "t" : "f";
                }
            }

            if (Source.Length == 1)
            {
                return Source;
            }
            else if(Source.Length != 3)
            {
                return string.Empty;
            }

            if (Source.Contains('&'))
            {
                return Source[0] == 't' && Source[2] == 't' ? "t" : "f";
            }
            else // Or
            {
                return Source[0] == 't' || Source[2] == 't' ? "t" : "f";
            }
        }
    }
}