xml format in stanford pos tagger

i have tagged 20 sentences and this is my code:

public class myTag {

public static void main(String[] args) {

    Properties props = new Properties();

    try {
        props.load(new FileReader("D:/tagger/english-bidirectional-distsim.tagger.props"));
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    MaxentTagger tagger = new MaxentTagger("D:/tagger/english-bidirectional-distsim.tagger",props);

    //==================================================================================================
    try (BufferedReader br = new BufferedReader(new FileReader("C:/Users/chelsea/Desktop/EN/EN.txt")))
    {

        String sCurrentLine;

        while ((sCurrentLine = br.readLine()) != null) {

            String tagged = tagger.tagString(sCurrentLine);
            System.out.println(tagged);
        }

    } catch (IOException e) {
        e.printStackTrace();
    }

}

}

this is the output:

as you can see in sentence node it has a Id attribute and here it's constantly=0 which it should not be.i expect the value=0,1,2,3,4,... i don't understand what is wrong with my code.