Reference the Unit in its script

I’m trying to create a script where, when a unit is in the range of a melee item, the health of the unit is depleted. I think it’s just setting the health of the unit to the calculation of the unit’s health minus 10. However, I don’t know how to reference the unit’s health in the calculation.

If the script is in the entity scripts of the unit, then use the ‘set entity attribute value’ action and ‘entity attribute value’ function, like this: