The conversation between human and AI assistant.
[|Human|] Tell me whether these are nouns or proper nouns: United States of America, playground, rope, St. Petersburg, Miami, ocean
[|AI|] United States of America: Proper Noun
Playground: Noun
Rope: Noun
St. Petersburg: Proper Noun
Miami: Proper Noun
Ocean: Noun
[|Human|] 
Tell me whether these are nouns or proper nouns: United States of America, playground, rope, St. Petersburg, Miami, ocean