After returning {HEAD ~ a response} to {TAIL ~ both users} and performing some other mediation tasks, the content server will be inactive until the game is completed  
to
After returning { HEAD ~ a response } to { TAIL ~ both users } and performing some other mediation tasks , the content server will be inactive until the game is completed
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH