Olou, Wilderness's Redeemer

When Olou, Wilderness's Redeemer enters the battlefield, mill the top seven cards of your
library, then you gain 3 life for each creature
card and lose 2 life for each noncreature card
milled this way.
Pay X life where X is the total power among creatures in your graveyard: Return each
creature with converted mana cost X or less to
the battlefield.