looking into [1] I read that Wikidata supports 358 languages. Is it still true? For example, I tried to add label in language coded as "nan" (defined in ISO 639-3) and it worked. However it didn't worked for e.g. "arb", which is also part of the ISO 639-3 standard. So how many?

[1] VRANDEČIĆ, Denny, KRÖTZSCH, Markus. Wikidata: A Free Collaborative Knowledgebase. Communications of the ACM. 2014-10, Vol. 57 No. 10, 7885. DOI 10.1145/2629489. http://cacm.acm.org/magazines/2014/10/178785-wikidata/fulltext