I need the formula

In the Driving Form worksheet, you will enter individual legs of a driving itinerary. The mileage between starting and ending cities is calculated in cell F6. Currently that cell displays an error value because no cities have been specified in cells D6 and E6. Revise the formula in cell F6 so that it displays a blank text string in place of an error value. A B D E F Distance #N/A Enter Proposed Leg Leg Starting City 1 Appleton Beloit Brookfield Delafield Eau Claire Fond du Lac Fort Atkinson Green Bay Kenosha La Crosse Lake Geneva Madison Marshfield Merrill Milwaukee Mineral Point Monroe Neenah Ooonomowoc Oshkosh Platteville Portage Racine Sheboygan Sturgeon Bay West Allis Whitewater Ending City #SPILL! Appleton Beloit Brookfield Delafield Eau Claire Fond du Lao Fort Atkinson Green Bay Kenosha La Crosse Lake Geneva Madison Marshfield Merrill Milwaukee Mineral Point Monroe Neenah Oconomowoc Oshkosh Platteville Portage Racine Sheboygan Sturgeon Bay West Allis bit