This is a story of my recent contest participation.

Let's call the Contest X. X was an international contest with online qualification rounds and the onsite Finals, with trip and hotel expenses covered by the organizer. In other words, X was a very important contest for me.

I was hoping to go to the Finals and participating in the qualification round. However, when I opened the last problem, I immediately remembered that the exact same problem was submitted to AtCoder before. I also knew that the submitter of that problem was included in the organizers of X.

Let's call the author of that problem Y. I immediately messaged Y about this issue. I first thought it was Y's mistake to forget that he submitted the problem to me, but the situation was a bit more complicated.

Y did remember he submitted the problem to me and he still used it in another contest. Why? Because I gave him a permission!

To make things clear, let me show you the log of the relevant chat between me and Y.