I want to know the answer to the following question:
Along with the Ukrainian Soviet Socialist Republic and Byelorussian Soviet Socialist Republic, what state joined Russia to form the Soviet Union?
All the background I'm provided with is that "Later treaty was included in the 1924 Soviet Constitution,[clarification needed] adopted on January 31, 1924 by the Second Congress of Soviets of the USSR.". Is that enough to answer the question?