/**

 * Created by sunny on 7/24/17.

 */

import java.util.*;

public class Solution {

    public  void solve(char[][] board) {

        if (board == null || board.length == 0) {

            return;

        }

        //首先将第一列和最后一列的O变为#

        for(int i = 0;i<board.length;i++){

            //这是按行遍历

            fill(board, i, 0);

            fill(board, i, board[i].length-1);

        }

        //将第一行和最后一行的O变为#

        for (int i = 0; i < board[0].length; i++) {

            fill(board, 0, i);

            fill(board, board.length-1, i);

        }

        //遍历整个数组，o变为X，#变为O

        for (int i = 0; i < board.length; i++) {

            for (int j = 0; j < board[i].length; j++) {

                if (board[i][j] == 'O') {

                    board[i][j] = 'X';

                }else if(board[i][j] == '#'){

                    board[i][j] ='O';

                }

            }

        }

    }

    private void fill(char[][] board,int row,int col) {

        if (board[row][col] == 'X') {

            return ;

        }

        board[row][col] = '#';

        Queue<Integer> queue = new LinkedList<>();

        //需要将元素的位置存储到 队列中 行和列

        int code = row * board[0].length + col;

        queue.add(code);

        while(!queue.isEmpty()){

            //找到这个元素

            int temp = queue.poll();

            //第几行

            int i  = temp/board[0].length;

            //第几列

            int j = temp%board[0].length;

            //看这个元素的四个周是不是O,上边

            if(i-1>=0&&board[i-1][j] == 'O'){

                board[i-1][j] = '#';

                queue.add((i-1)*board[0].length+j);

            }

            if (i+1<board.length&&board[i+1][j] == 'O') {

                board[i+1][j] = '#';

                queue.add((i+1)*board[0].length+j);

            }

            if (j-1>=0&&board[i][j-1] == 'O') {

                board[i][j-1] = '#';

                queue.add(i*board[0].length+j-1);

            }

            if (j+1<board[0].length&&board[i][j+1]=='O') {

                board[i][j+1] = '#';

                queue.add(i*board[0].length+j+1);

            }

        }

    }

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        char[][] board = new char[][]{

                {'X','X','X','X'},

                {'X','O','O','O'},

                {'X','O','X','X'},

                {'X','X','X','X'}

        };

        Solution solution = new Solution();

        solution.solve(board);

        for(int i=0;i<board.length;i++){

            for(int j=0;j<board[i].length;j++){

                System.out.print(board[i][j]);

            }

            System.out.println();

        }

    }

}