60638
The land frontier has three border crossings at Silistra , Kardam and Durankulak at the Black Sea .
 Silistra, Kardam, Durankulak, Black Sea
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Silistra, Kardam, Durankulak, Black Sea