#!/usr/bin/perl

# http://perlmonks.org/?node_id=1144184

use strict;
use warnings;

sub e
  {
  /\Gua/gc ? return e() : /\Gu/gc || return 0;
  1 while (/\Gd/gc && e() && /\Gf/gc or /\Gb/gc) && e() or /\Gc/gc;
  return 1;
  }

for (qw( u udufu uau uu uc ubu ucbuc uaau ua uauau uccc uauuau ))
  {
  print e() && /\G\z/ ? "matches" : "   fail", "  $_\n";
  }