Not Node
This is one of the most common logic nodes, along with AND and OR.
It inverts a boolean value - turning a true into a false and vice-versa.
This node is used in all modules.
Inputs
Run (Input #1) is a boolean value - a true or a false.
Outputs
Output #1 is the opposite value of what is put into Input #1. If the input is true, the output will be false, and vice-versa.