countif in the last 5 sheets

Hi

I have a workbook that has 20 sheets.
I need to count the number of 2 in column A of the last 5 sheets.
Bearing in mind that whenever i run the macro the page name may change.

here is what i have to do before counting the number of 2's in column A:

If Sheets.Count > 4 Then
    For i = Sheets.Count - 4 To Sheets.Count
        If Not flg Then
            Sheets(i).Select     
            
        Columns("A:A").Select
        Selection.Insert Shift:=xlToRight
        Range("A2").Select
        ActiveCell.FormulaR1C1 = _
        "=IF(AND(ISERROR(RC[2]),RC[1]<>""""),1,IF(AND(ISERROR(RC[2]),RC[1]=""""),2,""""))"

  Else
            Sheets(i).Select False
        End If
    Next
End If

so can any1 help?

thank you very much. You rhelp is much appreciated.

Sub test()
Dim i As Integer, myCount As Long
If Sheets.Count > 4 Then
    For i = Sheets.Count - 4 To Sheets.Count
        myCount = myCount + WorksheetFunction.CountIf(Sheets(i).Range("a:a"),2)
    Next
    MsgBox myCount
End If
End Sub

thank you so much
i would like to know how do you know what VBA codes to input when you want to count or something?.

is there any tutorial that i can read up?

Thank you very much