Delete all contacts

How can I delete all contacts?

1. In the left menu (in sidebar) go to Address book->All contacts
2. Click Delete all contacts button. Depending on the viewport, it may be hidden under the More actions button (the symbol of three dots above each other)
3. Check the box I'm sure, what I'm doing
4. Click the Delete button
5. All your contacts will be permanently removed from the address book (and all groups)