(creating a thread cause there wasn’t any)
This puzzle is fine but it doesn’t follow the “only ASCII characters” rule, typically because of the Hungarian ő.
So, should we edit non ASCII characters in testcases/validators ? (Note that the author doesn’t seem to be active on CG at the moment.)
These are probably related. Puzzles with unicode in the title don’t get auto-generated threads. Even for CodinGame this is hard, how shall we master it? 
While updating the test cases do not affect existing solutions but could help future attempts to try solving it, I know no reason why this should not be done.
Technically, previous solutions would fail as with the ASCII version your search would be over when you reach “Erdos”.
But it’s only one character to change in the script to make it work again.
Maybe the best solution is to edit it but indicate the change in the statement so that people who go back to it see that they must slightly edit their solution.
Now I remember this puzzle. It is one of the very few (the only one?) puzzles I need to enable UTF-8 encoding in my source to make it pass in CG.
Changing the test case will fail all existing solutions. It seems it is not a good idea to do it this way.
I am thinking if I were to write the solution in C, it could have been a painful experience. I wrote the code in a local editor. Directly writing the code in CG’s online editor may have another (easier?) experience I haven’t tested it out.
I think we can just let it be. If kinds of improvement is really necessary, it could be a “warning” in the Input section notifying coders they have to pay attention to the non-ASCII character in input.