I just downloaded ImageMagick and am already in need of help.

434.png + data-1.png
The first batch of pngs has unique IDs, the other one (like data-1), counts from 1 to 199. As the IDs have an important meaning, the file should keep the name of the first picture (434.png) after merging.
Can someone help me out? I tried a couple of things, but nothing really worked and if you couldn't already tell, I am a complete newbie with things like that. Until now everything I needed was done with Photoshop actions.
Thanks already for your help, it's really appreciated!