In 2022, Smith paid $6,000 to the tax collector of Big City for realty taxes on a two-family house owned by Smith's mother. Of this amount, $2,800 covered back taxes for 2021, and $3,200 covered 2022 taxes. Smith resides on the second floor of the house, and his mother resides on the first floor. In Smith's itemized deductions on his 2022 return, what amount is Smith entitled to claim for realty taxes?