How to create a dash mechanic which only works if you have more than one collectible resource like coins in Mario

So I am making a game with Thor and want to create a Thunder Dash with Shift. I have added Thunder Bolt collectibles like coins in Mario but I want it to be so that whenever I press shift if I have one or more Thunder Bolt then be able to dash and if I dont then dont be able to dash if it makes sense.

I have put in the code I tried but it always goes into negative and ends up launching me backwards