Sub intersection()
n = Sheets(1).UsedRange.Rows.Count
Dim i As Integer
Dim j As Integer
Dim k As Integer
k = 1
For i = 1 To n
    For j = 1 To n
        If Cells(i, 1) = Cells(j, 2) Then
            Cells(k, "C") = Cells(j, "B")
            k = k + 1
        End If
    Next j
Next i