Delete leads but not contacts or accounts

Delete leads but not contacts or accounts

Hi,

I want to delete the Leads I have in the CRM but do not want the Contacts or Accounts that have been created to be deleted. I'm assuming that because I converted Leads to Contacts or Accounts that they are identified differently from Leads? 

Will I be okay deleting all Leads and the Contacts and Accounts will remain?

Many thanks for your help,
Kelly