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    <title>Document</title>
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<H1 id="H1"></H1>

<script>
    switch(5550-50+100)
    {
        case 100:
            document.getElementById("H1").innerHTML="The result is 100";
            break;
        case 300:
            document.getElementById("H1").innerHTML="The result is 300";
            break;
        default:
            document.getElementById("H1").innerHTML="The result is 500";
            break;
    }
</script>

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