Stuck with "Get input key time down"

I have 2 anim montages. One for key press and hold, then the other for release. Im trying to get the" key press down time", to work with “left mouse button” if pressed and held, but it doesnt seem to work.
For the branch in the “left mouse button” Im figuring how to press and hold and go to the power attack montage, then if not pressed and hold go to the normal attack.

The “get input key time down” works perfectly in “event tick”, I want to get this value into my left mouse event