Well, your solution says you need 1 fold for an 0.0001m paper to reach 0.0001m. There's your problem ;-)

Simple tests contain only few examples of what you can expect, but when you hit submit, it's gonna test all edge cases (negative numbers, 0, big numbers) and throw many random tests, so passing sample tests is just 1 step towards completion :P

Always write what language you're using, so we can help.

Try printing the values and see if that helps, or post the input here, so we can tell you why it should return 4.

This isn't a suggestion, so I'm closing it, but you can still reply.