There are seven coins with the same appearance, one of which is counterfeit. Lighter than real money. How many times can counterfeit money be found by weighing it with a balance? The writing process!

It belongs to the method of folding in half, with six blocks twice, 13 blocks three times, and so on. In fact, it is reverse thinking, starting with three pieces, you use it once; 4,5,6,7. You use it twice, 8, 9, 10,1,12, 13, 14,14. The condition is 2 n ≤ x < 2 (n+ 1), where x is the given capacity and n is the number of times. You got it? I wish you improve your level.