title: Count of substrings within string
body: <p>My program should do the following:</p>
  
  <ol>
  <li>User enters a string: University of the Cordilleras</li>
  <li>User enters the substring: er</li>
  <li>Program outputs the substring-count: 2 (Univ<b>er</b>sity of the Cordill<b>er</b>as)</li>
  </ol>
  
  <p>I should not use .str, but create my own method.</p>