71448
The only chemical elements that form stable homonuclear diatomic molecules at standard temperature and pressure ( STP ) ( or typical laboratory conditions of 1 bar and 25 " °C ) are the gases hydrogen ( H ) , nitrogen ( N ) , oxygen ( O ) , fluorine ( F ) , and chlorine ( Cl ) .
 H
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 H