Private Sub Worksheet_Change(ByVal Target As Range)
A = Target.Column
B = Target.Row
If A > 3 Then Exit Sub
Select Case A
Case 1
If Target.Offset(0, 1) = "" And Target.Offset(0, 2) = "" Then Exit Sub
Case 2
If Target.Offset(0, -1) = "" And Target.Offset(0, 1) = "" Then Exit Sub
Case 3
If Target.Offset(0, -2) = "" Or Target.Offset(0, -1) = "" Then Exit Sub
End Select
I = 0
Do Until Sheet1.Range("A" & 2 + I) = ""
If Sheet1.Range("A" & 2 + I) = Sheet2.Range("A" & B) And Sheet1.Range("B" & 2 + I) = Sheet2.Range("B" & B) And Sheet1.Range("C" & 2 + I) = Sheet2.Range("C" & B) Then