Three in a Row on a Chessboard

Given an $n\times n$ chessboard, multiple players are playing a tic-tac-toe game. Each player uses a unique letter to mark their moves. In this game, a player wins if they can align $3$ of their letters consecutively in a row, column, or diagonal.

Your task is to determine the winning player's letter from the current state of the chessboard.

inputFormat

The first line contains an integer $n$, representing the size of the chessboard. The next $n$ lines each contain a string of length $n$, representing the board's current state.

outputFormat

Output a single letter, which is the winner's letter. It is guaranteed that there is a winning move in the given board.

sample

3
XXX
OO.
OO.

X