251877
At his debut in Hamburg in 1888 , he played Tchaikovsky 's Piano Concerto No. 1 in B flat minor with the composer conducting .
 Hamburg, Tchaikovsky
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Hamburg, Tchaikovsky