Kelmar is the lessee of an office building for 20 years; the economic life of the building is estimated at 50 years. At the start of year 3, Kelmar subleases the entire building to Doriel for the remaining 18 years of the head lease, without any particular option or guarantee. Kelmar's controller proposes an operating lease, on the grounds that 18 years are only a small part of the 50-year life of the building. Which analysis do you adopt?