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_21716139_1 (destination VARCHAR, frequency VARCHAR, train_name VARCHAR)
### Question:
How many destinations have a weekly frequency and are named AC Express?
### Answer:
SELECT COUNT(destination) FROM table_21716139_1 WHERE frequency = "Weekly" AND train_name = "AC Express"