PayPal Subscription - Number of Payments

If I am creating a form with a  PayPal integration where I want to have a down payment of $500, followed by 5 monthly payments of $300 each (Totaling $2000)...Do I choose Number of payments 5 or 6? 

The down payment would be the first payment for the first month. So if you want 5 more payments after that, then you must choose 6 as the total number of payments.