How many Soviet republics were there?

In the Russian Empire, expansion was far less bloody. Consider the fact that the number of "foreigners" increased after joining Russia, which cannot be said about the Native Americans. And Belarus is essentially an artificial state, a mixture of Poles, Lithuanians, and Slavs. Can you remind me how the Poles "loved" Belarusians and Ukrainians, they "loved" them so much that they asked Russia for help.