'''Originally Posted By: Thomas Lithomaslcy2009@yahoo.com''' This question is asking either an even number of a's or an odd number of b's. I am wondering does that mean we don't need to satisfy both condition which a has to be even and b has to be odd. For example, does abba accept? Thanks for the attention. On Apr 15, 5:14 pm, thomaslcy2...@yahoo.com