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Construction of the second , Moskovsko-Petrogradskaya line began almost immediately after the initial opening of the metro .
 Moskovsko-Petrogradskaya
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Moskovsko-Petrogradskaya