I have a speadsheet with pultiple worksheets

worksheet Jan has Col F that contain Intitials such as CL and Col C that
contains letter and numbers, such as NCO15 or Uko15.

On worksheet Parts, I have a cell with the initial, and i need a formula
that counts how many times the innitial in that cell appear in Jan column F,
as long as the Jan Col C corresponding data begins with the letter N.

After much research I wrtote this formula:
=SUMPRODUCT((JAN!F:F=Parts!A3)*(JAN!C:C="n*")) However I am still getting
an error.. Can someone see where i am going wrong?