How many feet per second does a shell move where the height range is 23500?
CREATE TABLE table_20820 (
    "Gun" text,
    "m/v ft/s" real,
    "Shell (lb)" text,
    "Time to ft (m) at 25\u00b0 (seconds)" text,
    "Time to ft (m) at 40\u00b0 (seconds)" text,
    "Time to ft (m) at 55\u00b0 (seconds)" text,
    "Max. height (ft)" real
)
SELECT MIN("m/v ft/s") FROM table_20820 WHERE "Max. height (ft)" = '23500'
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: How many feet per second does a shell move where the height range is 23500? ### Input: CREATE TABLE table_20820 (
    "Gun" text,
    "m/v ft/s" real,
    "Shell (lb)" text,
    "Time to ft (m) at 25\u00b0 (seconds)" text,
    "Time to ft (m) at 40\u00b0 (seconds)" text,
    "Time to ft (m) at 55\u00b0 (seconds)" text,
    "Max. height (ft)" real
) ### Response: SELECT MIN("m/v ft/s") FROM table_20820 WHERE "Max. height (ft)" = '23500'