<html>
<script>
    if (window.testRunner)
        testRunner.dumpAsText();
</script>
<body>
<p>This test passes if it does not crash.</p>
<math xmlns="http://www.w3.org/1998/Math/MathML">
    <msub>
        <mi>X</mi>
        <mtr>3</mtr>
    </msub>
    <msub>
        <mi>Y</mi>
        <mtd>3</mtd>
    </msub>
    <msubsup>
        <mi>X</mi>
        <mtr>3</mtr>
        <mn>2</mn>
    </msubsup>
    <msubsup>
        <mi>Y</mi>
        <mtd>3</mtd>
        <mn>2</mn>
    </msubsup>
</math>
</body>
</html>