Why can't I read this XML values with XElement?

This is the XML:

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://ift.tt/Wr35qg">
    <Document>
        <LookAt>
            <longitude>51.84750492</longitude>
            <latitude>61.85536484</latitude>
            <range>4423610</range>
        </LookAt>
        <Style id="Filled_Label">
        </Style>
    </Document>
</kml>

And this is the code:

XElement doc = XElement.Load(UiUtils.GetABSPath + "/kml/MyFile2.kml");
XNamespace ns = XNamespace.Get("http://ift.tt/1Erz9zx");

var query = from x in doc.Elements(ns + "longitude")
            select x;

Response.Write(query.Count());

foreach (XElement item in query)
{
    Response.Write(item.Value);
}

but it does print nothing (0 elements). Where am I wrong?