References summations based on column and row number

Hi,
I will begin with the code:

For a = 10 To 23
        For b = 3 To 7
        
        If Workbooks(NewFile).Sheets(1).Rows(a).Columns(b).Interior.ColorIndex = 4 Then
            Sum(a, b) = Sum(a, b) + 1
            Workbooks(CurrentFile).Sheets(1).Rows(a).Columns(b) = Sum(a, b)
        End If
        
    
        Next

Essentially I want to have a list of summations based on column and row numbers so if I ask for Sum(1,2) it will give me the sum from row 1 column 2.
Any help would be appreciated.