This is the exact CAPTCHA that led me to delete my AirBnb account. I was just trying to log in and finally gave up after 5 or 6 attempts. The next day I tried again and was able to log in after the 3rd try. From what I understand, this CAPTCHA is also time based too. I was so frustrated at what they made me go through to just log in, that I just deleted my account.

Counting dice should be a task for a computer, not a human.