hacker.org

Today I had a look at the black box challenge.
I know what exactly the programm is doing. Now starting with the desired output, I step backwards and try to find the correct input parameter. Doing so, I found something, where it seems to be impossible to get the right factor. Sure, it is possible, quite a lot of people already solved this.
Hmm, hope the point where I'm having problems is clear to those who solved already and my post is not spoiling too much for those who haven't...
Any hints regarding this problem? Thanks

ping?

If you have written code which does what the given file does (or would do if it were executable), it should not be difficult to just loop through all possible input values and thus find the right one.

brute force? Good idea! that didn't cross my mind xD
got it. thx.