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Its ruins are situated some 15 " km north-east of the town of Serres , near the present-day village of Oreini , on the southern slopes of the Vrontous mountains .
 Serres, Oreini, Vrontous
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 Serres, Oreini, Vrontous