Instruction: Assess the user's sentiment in the provided review and select the appropriate sentiment option from the list as the answer.

Input:
I bought the very first issue of the Microsoft Natural keyboard when it came out. It lasted at least five years, after a terrible adjustment period of nearly three weeks. The next one lasted about 16 months. It went downhill for two or three keyboards after that. I've had several models, including the Elite and the Pro and the one with 99 buttons all over the place. The letters now wear off in six months unless you apply clear nail polish to the key tops right away and keep it up. You can't wash it in the shower any more, it no longer has good isolation inside. Use Dow Bathroom Bubbles on a microfiber cloth - rinse VERY carefully, holding the board upside down. Let it dry naturally, don't blow water all over with compressed air, the keyboard just isn't as sturdy as it used to be.

Your wrists/arms/hands can get so used to the comfort that it's impossible to buy a laptop because your wrists ACHE within minutes of using the usual flat keyboard. That's the only downside I see. Otherwise, this is the only affordable ergonomic keyboard around. Keep your receipts handy, tape them underneath the board, in case you have to use the warranty.

Options:
A: very positive
B: positive
C: neutral
D: negative
E: very negative
Answer: A: very positive