How many kids do I gotta have

Before I had kids, one thing they frequently said to me: "You have NO idea! Wait until you have kids."

Once we had a child, they told me:

"You have NO idea. It is a whole different story when you have two."

We had a second child, and I thought I had finally arrived at this mark of maturity and adulthood that seems to keep eluding me. Then I get the congratulatory email:

"It's when you have three that it gets real interesting."

How many kids do I need to have?