You and two other friends are planning on having a big night out on the town
After a few drinks at your place, you and your friends head out to a club that you heard is amazing
When you arrive, the security guard denies you all entry unless you each answer him with the correct corresponding number
He turns to your first friend and says "3"
Your first friend responds "5"
The security guard nods his head and lets him through
He turns to your second friend and says "6"
Your second friend responds "3"
The security guard nods his head and lets him through
He turns to you and says "9"
What do you respond?