Match m = Regex.Match(@"D:MassSendingSms\MassSendingSms\2d346b2d-f235-4256-be7c-e6f3471343d3.txt", "[C|D|E|F]:([\\]{1,2}[a-zA-Z0-9]+[\\]{1,2})+([a-zA-Z0-9-]+)[\.txt]"