In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Survey of complications of indocyanine green angiography in Japan .
### Output Text:
Survey of complications of <span class="chemical">indocyanine green</span> angiography in Japan . 