Problem with an evented script call that checks parties and such

[RoseSkye]

How do I check to see how big a party is with a script call? I'm trying to set up a common event that checks the party size. Is it something like

if $game_party.size[3] then blah blah blah de blah blah?

[G_G]

$game_party.actors.size == 3

Or you can use other operators. ==, >, >=, <=, <, etc...