title: HOWTO ad a unique id to each unique row?
body: <p>I have data in two columns: </p>
  
  <pre><code>a  1
  a  1
  a  2
  b  3
  b  4
  </code></pre>
  
  <p>In the list there is 4 unique rows. I would like to ad a unique id to each unique row.
  Like this:</p>
  
  <pre><code>1  a  1
  1  a  1
  2  a  2
  3  b  3
  4  b  4
  </code></pre>
  
  <p>Of course I have many more rows and columns and date are more complex than in this example.</p>
  
  <p>Anyway to do this i excel? 
  Mvh Kresten Buch</p>