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_2417340_3 (vacator VARCHAR, date_of_successors_formal_installation VARCHAR)
### Question:
List the number of vacators when successors were formally installed on June 22, 1868.
### Answer:
SELECT COUNT(vacator) FROM table_2417340_3 WHERE date_of_successors_formal_installation = "June 22, 1868"