The rules that use the vocabulary item "n" are:

<nlb-careful>

n a

<nlb-not_command_or_system_utterance_or_user_response>

n a

<nlb-nlb7>

n a

<air_call_sign_prefix>

s n

<nlb-not_careful-nlb7>

n a

<air_call_sign_prefix-not_takes_digit>

s n

<nlb-nlb8>

n a

<nlb-not_careful-nlb8>

n a