Heliod's Intervention is a white instance for {XWW} with this wording:

Choose one —

  • Destroy X target artifacts and/or enchantments.
  • Target player gains twice X life.

How should this be interpreted? It's the and/or that confuses me.

Can I destroy up to X artifacts and up to X enchantments, for a total of 2*X permanents? Or can I only destroy up to X permanents, all of which have to be artifacts or enchantments?

If the last interpration is correct, targeting is easy. If X is 4 I can target for example 1 artifact and 3 enchantments.

If the first interpretion is correct, how does targeting work? I have to declare targets when casting the spell, so for each {1} in X, I have to have a legal target. If I wish to destroy 3 artifacts and 2 enchantments, can X be 3?