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_13967239_2 (senior__4th_year_ VARCHAR, junior__3rd_year_ VARCHAR)
### Question:
How many classes between senior and junior year for world history
### Answer:
SELECT COUNT(senior__4th_year_) FROM table_13967239_2 WHERE junior__3rd_year_ = "World History"