Checking for multiple values

Evening,

I am using this formula:

=SUMPRODUCT(('FFTA25%'!$U$2:$U$180="5a")*('FFTA25%'!$AC$2:$AC$180="C-"))

This allows me to add up how many time C- is in the column AC, if 5a is in the column U as well.

What I would like to change it to is count how many times C- or C or C+ is in column AC, if 5a is in column U as well.

Any help would be greatly appreciated.

Many thanks