67819
These were used for only a short time before being replaced by Yak-11 s and Yak-18 s in late 1952 .
 Yak-11, Yak-18
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:
 Yak-11, Yak-18