Angel of the Blinding Dawn

When Angel of the Blinding Dawn enters the
battlefield, Exile the top card of each player's
library. You may spend mana as though it were
any color to cast those cards.
{t}{x}: Create and X/X white Angel with flying
and lifelink. Then put a +1/+1 counter on each
angel you control.
At the beginning of your upkeep, if you control
20 or more angels, you win the game.