I have one shapefile with many polygons (at least 100). Each polygon has a value. Almost all these polygons overlap with each other. I want to sum the values of the polygons in the overlappings depend on which polygons overlap in that overlapping area. The picture (simplified sketch) hopefully explains this.
But I can't find a method to achieve this in ArcMap (I use Arcmap 10.2.2). I have tried many times the Union tool and others like Merge, but I can't find a solution.