What is the maximum specific impulse with a 4423 m/s effective exhaust velocity?
CREATE TABLE table_20439 (
    "Engine type" text,
    "Scenario" text,
    "SFC in lb/(lbf\u00b7h)" text,
    "SFC in g/(kN\u00b7s)" text,
    "Specific impulse (s)" real,
    "Effective exhaust velocity (m/s)" real
)
SELECT MAX("Specific impulse (s)") FROM table_20439 WHERE "Effective exhaust velocity (m/s)" = '4423'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the maximum specific impulse with a 4423 m/s effective exhaust velocity? ### Input: CREATE TABLE table_20439 (
    "Engine type" text,
    "Scenario" text,
    "SFC in lb/(lbf\u00b7h)" text,
    "SFC in g/(kN\u00b7s)" text,
    "Specific impulse (s)" real,
    "Effective exhaust velocity (m/s)" real
) ### Response: SELECT MAX("Specific impulse (s)") FROM table_20439 WHERE "Effective exhaust velocity (m/s)" = '4423'