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_1847180_3 (reason_for_change VARCHAR, vacator VARCHAR)
### Question:
How many reasons were given when A. Willis Robertson (D) resigned?
### Answer:
SELECT COUNT(reason_for_change) FROM table_1847180_3 WHERE vacator = "A. Willis Robertson (D)"