I'm using a JIRA instance for which I'm not the admin, so I don't have the option of installing plugins. I'm trying to filter to find issues in a particular project that don't have a parent (aren't sub-tasks of something else), but I can't figure out a good way to do so. The following query returns issues with a particular parent with the ID 84, but I'm not sure how to tweak it to get issues with no parent:
project = FOO AND Status = Open AND parent = FOO-84