78521
Very little is known of the missions he was part of , apart from the missions to North Vietnam in 1971 and to China the following year .
 North Vietnam, China
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:
 North Vietnam, China