using System;
using System.IO;

class MainClass {
    static void Main(string[] args) {
        DirectoryInfo MyDirectoryInfo = new DirectoryInfo("c:\\Nathan");
        Console.WriteLine("Total size: " + CalculateDirectorySize(DirectoryInfo, true).ToString() + " bytes.");

    }

    static long CalculateDirectorySize(DirectoryInfo Mydirectory, bool includeSubdirectories) {
        long totalSize = 0;

        FileInfo[] Myfiles = Mydirectory.GetFiles();
        foreach (FileInfo file in Myfiles) {
            totalSize += file.Length;
        }

        if (includeSubdirectories) {
            DirectoryInfo[] Mydirs = Mydirectory.GetDirectories();
            foreach (DirectoryInfo dir in Mydirs) {
                totalSize += CalculateDirectorySize(dir, true);
            }
        }

        return totalSize;
    }
}