UF(UnidaddeFomento) is a unit of account belonging to Chile. It doesn't have any coins or paper money. Its value is related to the Chilean peso. UF is used to price mortgages, loans, taxes, rents, etc. The price of items priced by UF will remain unchanged but its exchange rate with peso will fluctuate. If the rent of a house is 2UF per month, the actual monthly peso will be different with the exchange rate of UF.