How many reasons were given when A. Willis Robertson (D) resigned?
CREATE TABLE table_22347 (
    "State (class)" text,
    "Vacator" text,
    "Reason for change" text,
    "Successor" text,
    "Date of successors formal installation" text
)
SELECT COUNT("Reason for change") FROM table_22347 WHERE "Vacator" = 'A. Willis Robertson (D)'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: How many reasons were given when A. Willis Robertson (D) resigned? ### Input: CREATE TABLE table_22347 (
    "State (class)" text,
    "Vacator" text,
    "Reason for change" text,
    "Successor" text,
    "Date of successors formal installation" text
) ### Response: SELECT COUNT("Reason for change") FROM table_22347 WHERE "Vacator" = 'A. Willis Robertson (D)'