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_15944_5 (specific_impulse__s_ INTEGER, effective_exhaust_velocity__m_s_ VARCHAR)
### Question:
What is the maximum specific impulse with a 4423 m/s effective exhaust velocity?
### Answer:
SELECT MAX(specific_impulse__s_) FROM table_15944_5 WHERE effective_exhaust_velocity__m_s_ = 4423