This problem https://codeforces.me/contest/285/problem/B says "Consider all glasses are moving simultaneously during one shuffling operation.".

I don't understand how simultaneously makes sense, I solved the problem assuming one shuffling operation means moving the glasses in sequence* but I was just wondering if there is something I misunderstood.

* "if glass 1 goes from 1 to 2 and glass 2 goes from 2 to 3 then if marble was in 1 it ends up in 3" was my assumption.

Thank you for your help.