Files-snapshot date format (Synology)

Hello! I am trying to set up the files-snapshots app on my Nextcloud instance. In the documentation, it suggests using a date format like this:

if your snapshot is named like this: autosnap_2017-05-27_00:00:01_hourly

but my snapshots (Synology server) are in this format:

and I cant figure out the proper date format to enter into the “date format” section of the settings to make the snapshots appear. Any ideas? Thanks!