amcharts Replicating value axis on both left and right

HTML

<script src="http://www.amcharts.com/lib/amcharts.js" type="text/javascript"></script>
<div id="chartdiv" style="width: 100%; height: 355px;"></div>

JavaScript

var chart;

var chartData = [{
    country: "USA",
    visits: 4025},
{
    country: "China",
    visits: 1882},
{
    country: "Japan",
    visits: 1809},
{
    country: "Germany",
    visits: 1322},
{
    country: "UK",
    visits: 1122},
{
    country: "France",
    visits: 1114},
{
    country: "India",
    visits: 984},
{
    country: "Spain",
    visits: 711},
{
    country: "Netherlands",
    visits: 665},
{
    country: "Russia",
    visits: 580},
{
    country: "South Korea",
    visits: 443},
{
    country: "Canada",
    visits: 441},
{
    country: "Brazil",
    visits: 395},
{
    country: "Italy",
    visits: 386},
{
    country: "Australia",
    visits: 384},
{
    country: "Taiwan",
    visits: 338},
{
    country: "Poland",
    visits: 328}];


AmCharts.ready(function() {
    // SERIAL CHART
    chart = new AmCharts.AmSerialChart();
    chart.dataProvider = chartData;
    chart.categoryField = "country";
    chart.startDuration = 1;

    // AXES
    // category
    var categoryAxis = chart.categoryAxis;
    categoryAxis.labelRotation = 45;
    categoryAxis.gridPosition = "start";
    
    var valueAxis = new AmCharts.ValueAxis(); 
    valueAxis.position = "left"; 
    chart.addValueAxis(valueAxis); 
    
    var valueAxis2 = new AmCharts.ValueAxis(); 
    valueAxis2.position = "right"; 
    chart.addValueAxis(valueAxis2);

    // value
    // in case you don't want to change default settings of value axis,
    // you don't need to create it, as one value axis is created automatically.
    // GRAPH
    var graph = new AmCharts.AmGraph();
    graph.valueField = "visits";
    graph.balloonText = "[[category]]: [[value]]";
    graph.type = "column";
    graph.lineAlpha = 0;
    graph.fillAlphas = 0.8;
    graph.valueAxis = valueAxis;
    chart.addGraph(graph);
    
    var graph = new AmCharts.AmGraph();
    graph.valueField = "visits";
    graph.balloonText = "";
    graph.lineAlpha = 0;
    graph.valueAxis = valueAxis2;
    chart.addGraph(graph);

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