Wiktionary
not even one
det. None at all.
Usage examples of "not even one".
Then my mum explains how the stair lift works, how you have to move a little lever to make it go and how it stops as soon as you take your hand off the lever, making it impossible to hurt yourself, at least thats the theory, and how theres a little wooden landing newly built at the top of the stairs so that there is not one step to climb, not even one.
No Persian emperor would have risked himself against those huge guns in a cockleshell galley, not even one so bold as Khusrau.