That's weird... Maybe it means that the tests are not sufficient enough. Or maybe your code was on the edge of being fast enough.

OK, the code passed the test after clicking on the Attempt button a sufficient number of times.

You provided no language, no information, no test cases, no explanations, just the old classic "it runs perfect on my machine".

No, your code is simply wrong. And because you didn't care to elaborate, that's all I can conclude. This is not a KATA issue, but an issue with your code ( = question )

Try to print the input in whatever language you're using and track where it goes wrong ( also: READ THE ERROR MESSAGES! ). If you're still stuck, please open with a new question, and more information :P