How to read an element in XML file in powershell?

I have an XML file looks like this :

<?xml version="1.0" encoding="UTF-8"?>
<INITIAL>
    <FB1> fr <FB1>
    <FB2> fs <FB2>
    <FB3> ft <FB3>
    <FB4> fu <FB4>
    <FB5> fv <FB5>
    <FB6> fw <FB6>
    <FB7> fh <FB7>
    <FB8> gK <FB8>
    <FB9> fg <FB9>

</INITIAL>

I just want to read element FB1 tp FB9 and convert it to string, be like this :

frfsftfufvfwfhgKfg

$XML = Get-Content "C:\Users\initial.xml"
$XML