"One." That he knows. Others from his world, too, judging by what Law said, but he hasn't met them yet and is cautious about doing so for multiple reasons. Only the one matters anyway.

"Law is here. Closer to my age now." That last fact seems necessary to add, to justify why he's able to accept that Law died and smile about his presence here. It's still terrible, he still died far too young, but at the very least he got to live beyond childhood.