How many gold coins are there in the dirty water gate of the specialty store?

Special store dirt door 40 thousand gold coins. A patient with S needs 100, which is 680 *100 = 68,000 gold coins. Due to the privileged points, you can get one more piece for every three pieces (680 points at a time? It takes 2080 to buy 2040 for three times) In theory, you only need 70-80,680 gold coins to get an S-forbearance in the privilege.