We found an even bigger directory tree hiding a flag starting at /problems/57a246295d1345729cbddf98c16fcaed. It would be impossible to find the file named flag manually...
Is there a search function in Linux? Like if I wanted to 'find' something...
I alluded to this earlier, so there's not much to say. The literal command I put in was "find forest -name 'flag'".