The exchange system invalidates a conventional coupon and prints an exchange system coupon for {HEAD ~ a product} promoted by {TAIL ~ the coupon exchange system} 
The exchange system invalidates a conventional coupon and prints an exchange system coupon for { HEAD ~ a product } promoted by { TAIL ~ the coupon exchange system }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL