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_12221135_3 (arrival VARCHAR, operator VARCHAR, calling_at VARCHAR)
### Question:
How many trains call at Castor, Overton, Peterborough East and are operated by LNWR?
### Answer:
SELECT COUNT(arrival) FROM table_12221135_3 WHERE operator = "LNWR" AND calling_at = "Castor, Overton, Peterborough East"