47193
It is constrained by the Pontic Mountains to the south , Caucasus Mountains to the east , Crimean Mountains to the north , Strandzha to the southwest , Balkan Mountains to the west , Dobrogea Plateau to the northwest , and features a wide shelf to the northwest .
 Pontic Mountains, Caucasus Mountains, Crimean Mountains, Strandzha, Balkan Mountains, Dobrogea Plateau
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Pontic Mountains, Caucasus Mountains, Crimean Mountains, Strandzha, Balkan Mountains, Dobrogea Plateau