title: Sumif Formula with no duplicates
body: <p>I am trying to have sumif formula which avoid duplicates.  For example if something has been summed in the above rows, I don’t want it to be summed again if it’s down in the below rows, can you please assist?</p>
  
  <pre><code>=SUMIF($R$50:$R$54,R50,$AG$50:$AG$54)
  </code></pre>
  
  <p>Thanks</p>