A small strip$-$mining coal company is trying to decide whether it should purchase or lease a new clamshell. If purchased, the $$shell$$ will cost $$177500$ and is expected to have a $$47500$ salvage value after $6$ years. Alternatively, the company can lease a clamshell for only $$14000$ per year, but the lease payment will have to be made at the beginning of each year. If the clamshell is purchased, it will be leased to other strip$-$mining companies whenever possible, an activity that is expected to yield revenues of $$7000$ per year. If the company$$s MARR is $11\mathrm{.}00\%$ per year, should the clamshell be purchased or leased on the basis of a future worth analysis? Assume the annual M&O cost is the same for both options. $($Include a minus sign if necessary.$)$