checking duplicate in multiple column in VBA?

hi,

how can I add column 1,2,3 here instead of column 3 only?
I want to compare three column to get the unique value.

str=ar(i, 3)

Option Explicit

Sub SumandRemove()
    Dim ar As Variant
    Dim i As Long
    Dim j As Long
    Dim n As Long
    Dim str As String
   
    n = 1
    ar = Sheet1.Cells(10, 1).CurrentRegion.Value
    With CreateObject("Scripting.Dictionary")
        For i = 2 To UBound(ar, 1)
            str = ar(i, 3)
            If Not .exists(str) Then
                n = n + 1
                For j = 1 To UBound(ar, 2)
                    ar(n, j) = ar(i, j)
                Next
                .Item(str) = n
            Else
                For j = 7 To UBound(ar, 2)
                    ar(.Item(str), j) = ar(.Item(str), j) + ar(i, j)
                Next
            End If
        Next
    End With
    Sheet2.Range("A1").Clear
    Sheet2.Range("A1").Resize(n, UBound(ar, 2)).Value = ar
End Sub