The car comes with two sets of keys, each containing two keys: a larger one for the ignition switch, and a smaller one for the door and trunk locks. The ignition key number is on the flag that holds the keys together (shown by arrow).
The key number for the door and trunk locks is stamped on the key itself or on a tag included with the keys of a new car.
Using key numbers, you can order duplicates in case of breakage or loss of a key.