title: Get max value in pair
body: <p>I have many pairs with form:</p>
  
  <ul>
  <li>itemid core</li>
  <li>1       2</li>
  <li>1       4</li>
  <li>1       3</li>
  <li>2       2</li>
  <li>2       5</li>
  </ul>
  
  <p>I want to get max score for other itemid
  result</p>
  
  <ul>
  <li>itemid core</li>
  <li>1       4</li>
  <li>2       5</li>
  </ul>
  
  <p>Solution?</p>