I got TL12 1352E - Special Elements 81381374, but after changing set to unordered_set 81381997 I got AC, but the first version got TL on test, where the set(and unordered_set) stays empty(because maximum is 1 and P[i + 2] = P[i] + 2 in that test). I thought this was happening because of the organization of set, but version, where i only create set and don't use it at all passed tests 81382268. How can this be explained?