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 (frequency VARCHAR, train_no VARCHAR)
### Question:
What is the frequency of trains numbered 12671/12672?
### Answer:
SELECT frequency FROM table_21716139_1 WHERE train_no = "12671/12672"