What song is playing? Inspired by this xkcd

You work for Shazam and they have a project for you. Some customers are complaining about their app taking up too much space on their phone, so they want you to code a lite version of the app. Unfortunately, your existing code can only understand the word &quot;na&quot;, and you have to ship soon. That's okay, we'll do the best with what we've got.
The Challenge
You must write a full program that takes a user input, or takes a command line argument, and print the title and artist of the song. Since we are trying to fix customers complaining about program size, your code must be as short as possible. The input will be a string consisting entirely of na's, with a single space between them. Lowercase/uppercase is arbitrary. This is considered a valid input: Na Na nA na NA This is an invalid input: nah nah NA naNa banana You must determine what song is playing and print it out in exactly this format:
Song: &lt;trackname&gt;
Artist: &lt;artist&gt;

If the input is exactly 8 na's, this matches two separate songs, so you must print both:
Song: Batman Theme
Artist: Neal Hefti

and
Song: Na Na Hey Hey Kiss Him Goodbye
Artist: Steam

If the input is exactly 10 na's, you must print:
Song: Katamari Damacy
Artist: Yuu Miyake

If the input is exactly 11 na's, you must print:
Song: Hey Jude
Artist: The Beatles

If the input is 12 or more na's, you must print
Song: Land Of 1000 Dances
Artist: Wilson Pickett

Lastly, if the input is invalid, there are less than 8 na's, or any of the words are not &quot;na&quot;, your program fails to understand the music. So logically, there is only one other song that it could possibly be. You must print:
Song: Africa
Artist: Toto

As usual, standard loopholes apply, and the shortest answer in bytes wins.
Retina, 242

Try it online!

iG`^na( na)*$
iM`na
m`^8$
&gt;Batman Theme,Neal Hefti$n&gt;Na Na Hey Hey Kiss Him Goodbye,Steam
m`^10$
&gt;Katamari Damacy,Yuu Miyake
m`^11$
&gt;Hey Jude,The Beatles
[0-9].+
&gt;Land Of 1000 Dances,Wilson Pickett
m`^[0-9]
&gt;Africa,Toto
&gt;
Song: 
,
$nArtist: 


How it works:

IgnoreCase flag + Grep mode flag + Regex ^na( na)*$. If the input is valid, print it as is. If not, print nothing.

iG`^na( na)*$


IgnoreCase flag + Match mode flag + Regex na. Count the "na"s and print the number.

iM`na


If the string is exactly "8", replace by the second line.

m`^8$
&gt;Batman Theme,Neal Hefti$n&gt;Na Na Hey Hey Kiss Him Goodbye,Steam


If the string is exactly "10", replace by the second line.

m`^10$
&gt;Katamari Damacy,Yuu Miyake


If the string is exactly "11", replace by the second line.

m`^11$
&gt;Hey Jude,The Beatles


If the string matches [0-9].+, replace by the second line. This is neither true for single digit numbers, 10 and 11 as they already have been repaced nor any of the above replacement strings.

[0-9].+
&gt;Land Of 1000 Dances,Wilson Pickett


If none of the above matched, the string still starts with a number. Default to Toto, Africa.

m`^[0-9]
&gt;Africa,Toto


Replace the placeholders &gt; and , by Song: and Artist:.

&gt;
Song: 
,
$nArtist: