The Russian language is an East Slavic language primarily spoken in Russia and several other countries of the former Soviet Union. It is the most widely spoken Slavic language and is known for its rich literary tradition, with famous authors like Leo Tolstoy and Fyodor Dostoevsky contributing to its cultural heritage. Russian uses the Cyrillic alphabet, which consists of 33 letters. The language is characterized by its complex grammar, including six cases for nouns, which affect how words change form based on their role in a sentence. Russian is also an official language of the United Nations.