Great solution!
it is not valid for the second ine though!

Hi. When posting code, please mark it as having spoiler content, otherwise everyone on frontpage can see your code. Also format it properly (link here)

I don't know exactly how wrong it is, but I don't see you handling lower or upper case letters, to begin with...

Sample tests are just examples, there's a lot more tests run when you hit submit to make sure your solution is correct, and if you're getting errors, it probably means it isn't.