the network cost for operating the modified network topology is greater than or equal to {HEAD ~ the network cost} for operating {TAIL ~ the current network topology} 
for operating
the network cost for operating the modified network topology is greater than or equal to { HEAD ~ the network cost } for operating { TAIL ~ the current network topology }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL