Rss atom reader - limit to first few posts??

I'm building an rss reader using this code:  

        XmlReader reader = XmlReader.Create("http://www.example.com/blog/atom.xml");
        Atom10FeedFormatter formatter = new Atom10FeedFormatter();
        formatter.ReadFrom(reader);
        reader.Close();

        Repeater1.DataSource = formatter.Feed.Items;
        Repeater1.DataBind();
So far so good. Now I need to limit it so that just the top 3 items show, rather than all of them. What's the best way to accomplish this?

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