title: Values printed are different when debugging
body: <pre><code>cnt = 0
  s = 'aghe'
  s_len = len(s)
  s_len = s_len - 1
  while s_len &gt;= 0:
      if s[s_len] in ('aeiou'):
          cnt += 1
      s_len -= 1
      break;
  print ('numofVowels:'),cnt  
  </code></pre>
  
  <p>This does print the value of <code>cnt</code>. When debugging, <code>cnt</code> has the correct value!</p>