Fold variable of all instances

Hi, constructers.

I`ve got planets with units on it (instance "planet", variable "unit") and now i need to get a total amount of units on all planets (all planets are the same object). Can anyone tell me how to do this or give some advice? (like "go get some sleep" :))

No-way-variants:

Every tick - Set global\local variable to planet.units.

Every tick pick all planets - Set global\local variable to planet.units.

I`m not a new at C2 but, whoa, now i feel myself like a noob.

One variable : All_Units

Every tick/every X second:

Set All_Units to 0

Sub event For all planets:

Add to All_Units planets.units

I think this should work

Hey, thanks a lot, that`s almost it.

"Pick all Planet" doesn`t work, but "For each Planet" works perfect. All i needed is "Set All_Units to 0".

Karma and love to you :)