I'm quiting smoking after 10 years! (I'm 25 and it's been 5 days in a row now!! )

and to help me I created an excel file with a calendar

When I smoke I put F below the date and X if I don't smoke. I want a formulas that count the number of X in a row example:

F F X F F X F X X X X X ( each letter are in a different cell and I want the result to be 5 not 7 )

Any idea ?!

Thank you