acquiring, from the product information storage unit, color information on related products that differ in {HEAD ~ color} from {TAIL ~ the products} 
acquiring , from the product information storage unit , color information on related products that differ in { HEAD ~ color } from { TAIL ~ the products }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL