110177
While Karl Marx and Friedrich Engels defined communism as a political movement , there were already similar ideas in the past which one could call communist experiments .
 Karl Marx, Friedrich Engels
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:
 Karl Marx, Friedrich Engels