Add variables from the same array to each other

How do I add variables from the same array to each other? Let’s say I have an array of floats and I want the sum of all those floats. The “for each loop” works to get each individual variable, but as there’s only one output, I can’t use the “add” node. I’ve tried to find other nodes that could help me do this, such as creating a new local variable at runtime from each array index and add them to each other, but I can’t find anything of that kind either. Any suggestions?

(I’m working on an inventory system and I want to calculate whether the inventory is full or not.)