Need a report for Task-less agreements

I have had an extreme amount of agreements where the Task errored out.  The contract is not in any end date (Fully Signed, Cancelled, etc.), but there is no longer a Task assigned.  I need to find a list of all of these agreements so that I can go in and manually clean them. 

I have a report that pulls up any agreement that does not have an end state status, but can’t figure out how to remove those that still have Tasks assigned (these are easy to find and we won’t need them on the list).  Does anyone know how to do that?  I need it to find contracts with no Task, but one of several Attributes.