Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_1307572_1 (reverse VARCHAR, diameter VARCHAR)
### Question:
How many coins have a diameter of 23mm?
### Answer:
SELECT COUNT(reverse) FROM table_1307572_1 WHERE diameter = "23mm"