If you have fewer than X cards in your library, you reveal all of them.

A permanent card is an artifact, creature, enchantment, land, or planeswalker card.

The converted mana cost of a card in your library is determined solely by the mana symbols printed in its upper right corner. The converted mana cost is the total amount of mana in that cost, regardless of color. For example, a card with mana cost has converted mana cost 5.

If the mana cost of a card in your library includes , X is considered to be 0.

If a card in your library has no mana symbols in its upper right corner (because it's a land card, for example), its converted mana cost is 0. Such cards can always be put onto the battlefield with Genesis Wave.

You don't have to put permanent cards revealed this way onto the battlefield if you choose not to, regardless of their converted mana costs.