title: pandas - merge and uniquely rename the columns of two data-frames with same column names
body: <p>I have two dataframes like the ones below:</p>
  <pre><code>dataframeA
  bagle scom others
  111   222  333
  111   222  333
  
  dataframeB
  bagle scom others
  444   555  666
  444   555  666
  </code></pre>
  <p>I'd like to merge dataframeA &amp; dataframeB (same columns' name) into:</p>
  <pre><code>dataframeA&amp;B
   A     B     C    D    E      F
  111   444   222  555  333    666
  111   444   222  555  333    666
  </code></pre>
  <p>what should I do?</p>