Mystic of the Hidden Lands

Mystic of the Hidden Lands cost {1} more to cast for each untapped land you control.
When Mystic of the Hidden Lands enters the battlefield, add {x} to your mana pool where X is the amount of mana spent to cast Mystic of the Hidden Lands.
Mystic of the Hidden Lands enters the battlefield with a +1/+1 counter for each land you control