2D histogram from many similar 1D histograms

Hi Rooters!

I have a file with many similar TH1D histos, one for each runnumber: each of it plots the number of entries (y-axis) for each chiSig (x-axis).

Is there a simple way to take all of these histos and put them into a 2D-histos plotting chiSig versus the runnumber?

Or do I have to fill every bin of the 2D histo individually?

I appreciate your help!!

All_chiSig-histos.root (1.78 MB)

see example of a script in attachment

t12d.C (1.79 KB)

Thanks a lot!