<?xml version="1.0" encoding="UTF-8"?>
<math xmlns="http://www.w3.org/1998/Math/MathML">
   <mrow>
      <mi>L</mi>
   </mrow>
   <mo>=</mo>
   <mfenced close="}" open="{">
      <msub>
         <mi>π</mi>
         <mn>1</mn>
      </msub>
      <msub>
         <mi>π</mi>
         <mn>2</mn>
      </msub>
   </mfenced>
</math>
