title: How to calculate total ip's of a subnet in AWS
body: <p>Recently we got an issue of IP running out in VPC due to huge IP's consumed by ENI. I need to write a script in boto3, to trigger an alert if total ip usage increases around 80% or something.</p>
  
  <p>Hence I need to know the Total ip's allocated in a subnet in VPC. I need the total count of used IP's and free IP's. </p>
  
  <p>Please share the boto3 commands for doing it.</p>