Say I topdeck Entreat the Angels and cast it for its miracle cost of XWW. But my opponent wants to counter it with a CMC-based effect, such as Spellstutter Sprite or Spell Burst.
202.3. The converted mana cost of an object is a number equal to the total amount of mana in its mana cost, regardless of color....
202.3b When calculating the converted mana cost of an object with {X} in its mana cost, X is treated as 0 while the object is not on the stack, and X is treated as the number chosen for it while the object is on the stack.
If I spent 5 mana to cast Entreat the Angels with X=3, what is the CMC of Entreat the Angels on the stack?
Do I get to double-count the X I spent because the card's base mana cost is XXWWW?
Or is X "zero" because I'm not actually paying the X in the mana cost?