X = Nxxxxxx000
Y = Nxxxxxx001

/^N.*(?!00)..$/  failure 278229/s     -- 
/^N.*(?<!00$)$/  failure 330512/s    19%
/^N(?!.*00$).*$/ success 536004/s    93%
/^N.*(?!00)..$/  success 540980/s    94%
/^N(?!.*00$)/    success 633900/s   128%
/^N(?!.*00$)/    failure 743994/s   167%
/^N(?!.*00$).*$/ failure 750772/s   170%
/^N.*(?<!00$)$/  success 789866/s   184%