title: Get number of rows in UICollectionView
body: <p>UICollection view automatically adjusts the number of rows based on the number of items per section and size of each cell.</p>
  
  <p>So is there a way to get the number of rows in an UICollectionView?</p>
  
  <p>For example: If I have a calendar with 31 days that automatically fit into n rows.
  How do I get the value of this 'n' ?</p>