48879
Background Military situation At 18:00 on 29 January 1968 , South Vietnamese forces began a 36-hour ceasefire in celebration of the arrival of the Year of the Monkey .
 Military, South Vietnamese forces
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Military, South Vietnamese forces