CF350B Resort

Valera's finally decided to go on holiday! He packed up and headed for a ski resort. Valera's fancied a ski trip but he soon realized that he could get lost in this new place. Somebody gave him a useful hint: the resort has $ n $ objects (we will consider the objects indexed in some way by integers from $ 1 $ to $ n $ ), each object is either a hotel or a mountain. Valera has also found out that the ski resort had multiple ski tracks. Specifically, for each object $ v $ , the resort has at most one object $ u $ , such that there is a ski track built from object $ u $ to object $ v $ . We also know that no hotel has got a ski track leading from the hotel to some object. Valera is afraid of getting lost on the resort. So he wants you to come up with a path he would walk along. The path must consist of objects $ v_{1},v_{2},...,v_{k} $ ( $ k>=1 $ ) and meet the following conditions: 1. Objects with numbers $ v_{1},v_{2},...,v_{k-1} $ are mountains and the object with number $ v_{k} $ is the hotel. 2. For any integer $ i $ $ (1

The first line contains integer $ n $ ( $ 1

In the first line print $ k $ — the maximum possible path length for Valera. In the second line print $ k $ integers $ v_{1},v_{2},...,v_{k} $ — the path. If there are multiple solutions, you can print any of them.