Where are you living?

Here in Argentina until this year we called "Russian" everyone form the former Soviet Union. Now I try to memorize the correct nationality of each immigrant, but I can't identify the country they are from. Can you distinguish Argentineans from Brazilians?

"The Soviet Union was an ethnically diverse country, with more than 100 distinct ethnic groups."[0] This was from 1960's the world is more blended now. What is something you think would make people think 'Russian' versus any other?

[0] https://rarehistoricalphotos.com/sketches-soviet-police-ethn...