I need a formula which calculates the number of occurences of a variable
apprearing in a column if the entry in another row is equal to N or n.

I have attempted to use the below but it shows a VALUE error message:

={countif(if(A1:A10="N",C1:C10),24)}

24 being the variable to be counted and C1:C10 is the range where the
variable is listed.