3327
The merged inverse - electron - demand hetero - Diels - Alder ( ihDA ) / retro - Diels - Alder ( rDA ) reaction sequence can be used to rapidly synthesise highly functionalised nitrogen heteroaromatics .
 Chemical: nitrogen
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: nitrogen