I'm assuming that you require something which will count the required value of a filtered list( in this case Column C of Sheet 2), then subtract the number of occurrences in Column A of Sheet 2, any of the values contained within the list in Column C of Sheet 3. Am I right so far?

The counting of a value in a filtered list is simply =CountIf($C$2:$C$83,C2) to be entered in cell C84.

It is after here that maybe XLD will come in with a possible Sumproduct formula to count the number of occurences of any of the nominated values found in Column A.