title: Get date in yyyymmdd (20180328) format
body: <ol>
  <li>Input Date in yyyymmdd (20180328) format.</li>
  <li>Get list of two previous months date (yyyymmdd).</li>
  <li>Output should be store in variable with format yyyymmdd so that I can use it later to run xyz in loop with all previous three months date. </li>
  </ol>
  
  <p>Eg:
  If I enter 20170828 ,then it will return me 
  <strong>20170828
  20170728 
  20170628</strong> 
  and I can use this outputs as input to xyz operation without calling xyz 3 separate times </p>