Artistic Rithmatist

When Artistic Rithmatist enters the
battlefield, name a card type. Exile cards from
the top of your library until you exile a card of
the chosen type. You may cast it without paying
its mana cost as long as you control a number of
Rithmatists equal to or greater than its converted
mana cost until end of turn. Put the exiled cards
on the bottom of your library in a random order.