实现一个简单的密码生成系统。一个有效的密码由L(3<=L<=15)个小写字母(来自传统的拉丁字母集 a ... z )组成，至少有一个元音字母( a , e , i , o 或者 u )，至少有两个辅音字母(除去元音以外的字母)，并且按字母表顺序出现(例如， acd 是有效的，而 dac 不是)。

给定一个期望长度L和若干个小写字母，写一个程序，打印出所有的长度为L、能由这些字母组成的有效密码。密码必须按字母表顺序打印出来-The realization of a simple code generation system. A valid password from the L (3 < = L < = 15) a lowercase letters (from the Latin tradition set ' a' ...'　z' ) composed of at least one vowel letter ( ' a' , ' e' , ' i' , ' o'　or ' u' ), at least two consonant letters (letters other than vowels removed), and appear in alphabetical order (for example, ' acd'　is valid, and '　dac ' instead). Expectations of a given length L and a number of lowercase letters, writing a program, print out all of the length L, can be composed by these letters effectively password. Password must be printed in alphabetical order