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_28787871_3 (production_code INTEGER, us_viewers__millions_ VARCHAR)
### Question:
What is the highest production code of the episodes having a US viewership of exactly 2.3?
### Answer:
SELECT MAX(production_code) FROM table_28787871_3 WHERE us_viewers__millions_ = "2.3"