ACME Drilling is evaluating an offshore oil-drilling platform for possible impairment. The company estimates the following: book value, $18.5 million; fair value, $12 million; sum of estimated future cash flows generated from the oil-drilling platform, $16 million. What amount of impairment loss, if any, should ACME record? (Enter your answer in millions rounded to 1 decimal place (i.e., 5,500,000 should be entered as 5.5).)