In the case of a failure to file a return of tax imposed by chapter 1 within 60 days of the date prescribed for filing of such return (determined with regard to any extensions of time for filing), unless it is shown that such failure is due to reasonable cause and not due to willful neglect, the addition to tax under paragraph (1) shall not be less than the lesser of $205 or 100 percent of the amount required to be shown as tax on such return
