<?xml version="1.0" encoding="UTF-8"?>
<math xmlns="http://www.w3.org/1998/Math/MathML">
   <msub>
      <mo>∑</mo>
      <mi>x</mi>
   </msub>
   <msub>
      <mo>∑</mo>
      <mi>y</mi>
   </msub>
   <mi>I</mi>
   <mfenced close=")" open="(">
      <mi>x</mi>
      <mi>y</mi>
   </mfenced>
</math>
