This is the 8032nd most frequent Russian word.
красноярска
"Красноярска" is the genitive form of "Красноярск," meaning "of Krasnoyarsk," a city in Russia.
Here, 'Красноярск' is used as a noun indicating the name of the city Krasnoyarsk.
Я поеду в Красноярск на следующей неделе.
I will go to Krasnoyarsk next week.
In this sentence, 'Красноярска' is in the genitive case, indicating origin or association.
Мой друг из Красноярска прислал мне подарок.
My friend from Krasnoyarsk sent me a gift.
This sentence uses 'Красноярск' in the nominative case to state the subject of the sentence.