vba code working but not when i start from 0

    Dim pref As String, myStr As String, x, LastR As Range
    pref = InputBox("Enter Prefix")
    myStr = InputBox("Enter datarange")
    If myStr = "" Then Exit Sub
    x = GetDetails(myStr)
    If IsArray(x) Then
        pref = pref & x(0)
        Set LastR = Sheets("Sheet1").[d8]
        If LastR <> "" Then Set LastR = LastR.Parent.Cells(Rows.Count, LastR.Column).End(xlUp)(2)
        LastR.Resize(Val(x(2)) - Val(x(1)) + 1) = Evaluate("""" & pref & """&row(" & x(1) & ":" & x(2) & ")")
    End If
End Sub

Function GetDetails(ByVal txt As String)
    With CreateObject("VBScript.RegExp")
        .IgnoreCase = True
        .Pattern = "^(.*?)(\d+) to (\d+)$"
        If .test(txt) Then GetDetails = Split(.Replace(txt, "$1^^$2^^$3"), "^^")
    End With
End Function