Ritual of the Construct says:
Response: After you discard 1 or more cards from your hand, place a success token on Ritual of the Construct.
Action: Exhaust Ritual of the Construct and discard X success counters from it to choose an opponent. That opponent must sacrifice a character with cost X or lower.
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If there are no success counters on the card, may I still use the action and choose x to be 0 to force my opponent to sacrifioce an insane character since insane characters are considered to have a cost of 0?