If the cost is impossible to determine, use of cost per unit to minimize {TAIL ~ the number} of {HEAD ~ hops} may be useful 
If the cost is impossible to determine , use of cost per unit to minimize { TAIL ~ the number } of { HEAD ~ hops } may be useful
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH