13399
If old friends return and new people also join in , and the number of stamp collectors again reaches 15 million or more , then we are honestly a little doubtful whether these few stamps will be enough for everyone to share .
 15 million
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: date, organization, person, geographical social political, national religious political, facility, cardinal, location, work of art, law, event, product, ordinal, percent, time, quantity, money, language 
Text: {0} 
Answer:
 15 million