A small company heats its building and spends $8,800 per year on natural gas for this purpose. Cost increases of natural gas are expected to be 10% per year starting one year from now (i.e., the first cash flow is $9,680 at EOY one). Their maintenance on the gas furnace is $340 per year, and this expense is expected to increase by 12% per year starting one year from now (i.e., the first cash flow for this expense is $380.80 at the EOY one). If the planning horizon is 13 years, what is the total annual equivalent expense for operating and maintaining the furnace? The interest rate is 18% per year