Countifs across multiple tabs

I am trying to count how many time the name "Bryan" appears in Range f:f across mutiple sheets in my worksheet.

My worksheet contains 9 sheets I am setting up my formula in sheet "Riders" column 2 where I have column of names in column 1. Sheets "28-310 - 36-310" have work assignments with the corresponding names in column F. Sheet "Riders" is being used to tally the number of times the names appear in the following sheets.

The formula I have tried unsuccesfully is =COUNTIFS('28-310'!F:F,Riders!A6,'29-310'!F:F,Riders!A6...). I've tried a variation of a suggestion from a previous post about the averageif function but was unsuccesful there too.

Thanks for any assistance you can render.

You can either pick a cell in each sheet and do a COUNTIF in each sheet, then sum those in one sheet with formula like: =SUM('28-310:36-310'!X1) where X1 was chosen cell in each sheet.

or in the summary sheet, list the sheetnames in 9 vertical says, say X1:X9, then try:

=SUMPRODUCT(COUNTIF(INDIRECT("'"&$X$1:$X$9&"'!F:F"),Riders!A6))