35000
The non-competitive concert featured the participation of 15 past Eurovision artists from 13 countries , performing songs from the history of the contest , alongside video montages of several other Eurovision songs and behind-the-scenes footage of historical contests featured in-between the on-stage performances .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None