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_name_18 (purpose VARCHAR, band VARCHAR, frequency VARCHAR)
### Question:
Band of am, and a Frequency of 0 846 has what purpose?
### Answer:
SELECT purpose FROM table_name_18 WHERE band = "am" AND frequency = "0 846"