In step 201, the tag extractor 121 extracts {TAIL ~ all HTML tags} from {HEAD ~ an e mail} in the plurality of e mails 
In step 201 , the tag extractor 121 extracts { TAIL ~ all HTML tags } from { HEAD ~ an e mail } in the plurality of e mails
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH