Just click on the card, and you don't need to spend much:

Pad card method: 5 cards, 2 cards with single card, and the probability is also 22%. Strengthen 15 times, see the law. My rule is: failure, failure, failure, success, failure, failure, success, failure, failure, failure, failure, success. Then as long as I fail 3-4 times in the last 5 enhancements, I can succeed with this rule. (For example, understand)

Is there a problem?

Hope to adopt