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_name_29 (acres VARCHAR, landfill VARCHAR, opened VARCHAR)
### Question:
What is the total number of acres at Sai Tso Wan, opening before 1978?
### Answer:
SELECT COUNT(acres) FROM table_name_29 WHERE landfill = "sai tso wan" AND opened < 1978