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A partial formalization of what would become the modern concept of algorithm began with attempts to solve the " Entscheidungsproblem " ( decision problem ) posed by David Hilbert in 1928 .
 David Hilbert
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 David Hilbert