Just click the card, you don't need to spend a lot of things:

Pad method: up to 5, with single 2, 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 I can succeed with this rule as long as I fail 3-4 times in the last 5 enhancements. (For example, understand)

Is there a problem?

Hope to adopt