Hadd not adding histograms but listing all directories in the output file instead

[ymag]

Hello,
I am trying to merge 2D histograms of two root files using hadd. Each root file contains many directories with multiple trees and histograms. Both root files have exactly the same structure. The target file I get contains 2 separate directories and the histograms under the directories are not merged or added As shown on the screenshot below, I need to get all histograms under Run_343266 and Run_343966 added.
Thank you for your help.

[Wile_E_Coyote]

The “hadd” utility will merge objects with the same names only.

To add histograms with different names, you need to use: TH1::Add

[ymag]

Thank you !