Merge duplicate rows and sum one column - VBA code

Sub ABC()
     
    Dim LASTROW As Long
    Dim I As Long
    Dim J As Long
    Dim K As Long
    Dim MyVALUE As Variant
    Application.ScreenUpdating = False
    LASTROW = Range("A" & Rows.Count).End(xlUp).Row
    For I = 1 To LASTROW - 1
        MyVALUE = Cells(I, "B") & Cells(I, "C")
        For J = I + 1 To LASTROW
            If (MyVALUE = Cells(J, "B") & Cells(J, "C")) Then
                For K = 1 To 13
                    If (Cells(I, K) = "") Then Cells(I, K) = Cells(J, K)
                Next K
                Cells(J, "A").EntireRow.Delete
            End If
        Next J
    Next I
    Application.ScreenUpdating = True
     '
End Sub

    ActiveSheet.Range("$A$1:$D$9").RemoveDuplicates Columns:=Array(2, 3), Header _
        :=xlNo