static void Main()
{
string path = @"C:\Windows";
FolderTree windowsTree = new FolderTree(path);
windowsTree = windowsTree.TreeDFS();
Folder appPatch = windowsTree.FindFolder(@"C:\Windows\AppPatch");
double sum = appPatch.CalculateFileSizeSum(appPatch) / 1048576;
Console.WriteLine(@"sum of files in C:\Windows\AppPatch = {0:0.00}mb", sum);
}