Chengdong的征途

这天chengdong在检测贪玩蓝月的时候，到了一个副本，副本介绍：“找到魔王一刀999级，橙装随便爆，金币捡捡检。。。”。但是chengdong发现里面的迷宫太简单了，魔王一下子就被发现了！chengdong反馈了这个问题后，贪玩蓝月就让chengdong来写一个代码，代码要求对随机给的一个n*m的迷宫，和一个k，要添加k堵墙；由此来增加游戏难度；但是chengdong觉得烦，就把这个任务交给了你，而且还根据他自己的美学对你提出了一个要求：你要让剩下的部分只有一个连通区域（设定是只能上下左右走）；

The first line contains three integers n, m, k (1 ≤ n, m ≤ 500, 0 ≤ k < s), where n and m are the maze's height and width, correspondingly, k is the number of walls Pavel wants to add and letter s represents the number of empty cells in the original maze.

Each of the next n lines contains m characters. They describe the original maze. If a character on a line equals ".", then the corresponding cell is empty and if the character equals "#", then the cell is a wall.

第一行输入三个整数n, m, k；（1<=n,m<=500, k<s, s是“.”的数量）

接下来n行，每行m个字符（“#”是墙， “.”是路）；

Print n lines containing m characters each: the new maze that fits Pavel's requirements. Mark the empty cells that you transformed into walls as "X", the other cells must be left without changes (that is, "." and "#").

It is guaranteed that a solution exists. If there are multiple solutions you can output any of them.

输出也是一个n*m的迷宫，在这个迷宫里，要有k个“X”，表示这里将添加一堵墙。

保证有解，有多种方案时，随便输出一种。

3 4 2
#..#
..#.
#...

#.X#
X.#.
#...

5 4 5
#...
#.#.
.#..
...#
.#.#

#XXX
#X#.
X#..
...#
.#.#