YNTKTS

This is a short form of "Ya ndak tau kok tanya saya". This sentence was used by the 7th president of Indonesia, Joko Widodo. The sentence translates (grammar-friendly) to "I don't know, why'd you ask me?" and roughly translates (non-grammar-friendly) to "Well I don't know, why ask me?"

This sentence is usually typed in the short form online.

John(fictional character): Pak, ada gak Indomaret di sini? (Sir, is there an Indomart here?)
Pak Budi: YNTKTS