CF818D Multicolored Cars

Alice and Bob got very bored during a long car trip so they decided to play a game. From the window they can see cars of different colors running past them. Cars are going one after another. The game rules are like this. Firstly Alice chooses some color $ A $ , then Bob chooses some color $ B $ ( $ A≠B $ ). After each car they update the number of cars of their chosen color that have run past them. Let's define this numbers after $ i $ -th car $ cnt_{A}(i) $ and $ cnt_{B}(i) $ . - If $ cnt_{A}(i)>cnt_{B}(i) $ for every $ i $ then the winner is Alice. - If $ cnt_{B}(i)>=cnt_{A}(i) $ for every $ i $ then the winner is Bob. - Otherwise it's a draw. Bob knows all the colors of cars that they will encounter and order of their appearance. Alice have already chosen her color $ A $ and Bob now wants to choose such color $ B $ that he will win the game (draw is not a win). Help him find this color. If there are multiple solutions, print any of them. If there is no such color then print -1.

The first line contains two integer numbers $ n $ and $ A $ ( $ 1

Output such color $ B $ ( $ 1

Let's consider availability of colors in the first example: - $ cnt_{2}(i)>=cnt_{1}(i) $ for every $ i $ , and color $ 2 $ can be the answer. - $ cnt_{4}(2)<cnt_{1}(2) $ , so color $ 4 $ isn't the winning one for Bob. - All the other colors also have $ cnt_{j}(2)<cnt_{1}(2) $ , thus they are not available. In the third example every color is acceptable except for $ 10 $ .