What is the doubtful account expense for the year ended December 31, 2009 if the Accounts receivable at December 31, 2009 is $440, the Allowance for Doubtful Accounts at January 1, 2009 is $64, the Accounts written off as uncollectible during the year is $44, and the net realizable value for the receivables at December 31, 2009 is $380?