Function R21Bul() As Integer

    Dim i As Long, sonuc As Integer

    Dim rg21 As Range, rg22 As Range

    

    Const donguSayisi As Integer = 2000

    

    With ThisWorkbook.Worksheets("Pergole")

        Set rg21 = .Range("B21"): Set rg22 = .Range("B22")

        For i = 2 To donguSayisi

            rg21.Value = i

            If rg22.Value >= 400 And rg22.Value <= 450 Then

                sonuc = i: GoTo var

            ElseIf rg22.Value < 400 Then

                sonuc = i - 1: Exit For

            End If

        Next i

        

        For i = sonuc To donguSayisi

            rg21.Value = i

            If rg22.Value > 450 Then

              sonuc = i: Exit For

            End If

        Next i

        

var:

        R21Bul = sonuc

    End With

End Function