Estair, Corrupted Explorer

Oblation (Each card you exile from the top of your library while casting this spell pays for {1}.)
Estair enters the battlefield with X +1/+1
counters on it, where X is the number of cards
you have in exile.
When Estair dies, you may return up to X cards
with different converted mana costs from exile to
your hand, where X is the number of +1/+1
counters on Estair.