upd: has been fixed now
This seems like a problem. On problem A, the statement guarantees 2≤n≤1014, but the validator accepts n=1, causing an invalid edge case for many solutions.
For example, this hack should not work. The input is just:
1
1
pinging {Supermagzzz, Stepavly, MikeMirzayanov}
It should be fixed, but the round is already unrated so IMO it doesn't affect much.
This doesn't affect the point of this blog, but as a side note, it seems strange that the statement doesn't allow n=1 in the first place.
It's a big mistake, I'll wix it. Thanks for the issue.