#include <cstdio>

char map[20][21];
int w, h;
int ans;
int x, y;
int xx, yy;
const int dx[4] = {0, 1, 0, -1}, dy[4] = {-1, 0, 1, 0};

void Move(int X, int Y) {
	ans++;
	map[Y][X] = '#';
	for(int i = 0; i < 4; i++) {
		xx = X + dx[i];
		yy = Y + dy[i];
		if(0 <= xx && xx < w && 0 <= yy && yy < h && map[yy][xx] == '.') {
			Move(xx, yy);
		}
	}
}

int main(void) {
	while(1) {
		ans = 0;
		scanf("%d %d", &w, &h);
		if(!w && !h) break;
		for(int i = 0; i < h; i++) {
			scanf("%s", map[i]);
			for(int j = 0; j < w; j++) {
				if(map[i][j] == '@') {
					x = j;
					y = i;
				}
			}
		}
		Move(x, y);
		printf("%d\n", ans);
	}
	return 0;
}
### Prompt

Please provide a cpp coded solution to the problem described below:

There is a rectangular room, covered with square tiles. Each tile is colored either red or black. A man is standing on a black tile. From a tile, he can move to one of four adjacent tiles. But he can't move on red tiles, he can move only on black tiles.

Write a program to count the number of black tiles which he can reach by repeating the moves described above.



Input

The input consists of multiple data sets. A data set starts with a line containing two positive integers W and H; W and H are the numbers of tiles in the x- and y- directions, respectively. W and H are not more than 20.

There are H more lines in the data set, each of which includes W characters. Each character represents the color of a tile as follows.

* '.' - a black tile
* '#' - a red tile
* '@' - a man on a black tile(appears exactly once in a data set)


The end of the input is indicated by a line consisting of two zeros.

Output

For each data set, your program should output a line which contains the number of tiles he can reach from the initial tile (including itself).

Examples

Input

6 9
....#.
.....#
......
......
......
......
......
#@...#
.#..#.
11 9
.#.........
.#.#######.
.#.#.....#.
.#.#.###.#.
.#.#..@#.#.
.#.#####.#.
.#.......#.
.#########.
...........
11 6
..#..#..#..
..#..#..#..
..#..#..###
..#..#..#@.
..#..#..#..
..#..#..#..
7 7
..#.#..
..#.#..
###.###
...@...
###.###
..#.#..
..#.#..
0 0


Output

45
59
6
13


Input

6 9
....#.
.....#
......
......
......
......
......
@...#
.#..#.
11 9
.#.........
.#.#######.
.#.#.....#.
.#.#.###.#.
.#.#..@#.#.
.#.#####.#.
.#.......#.
.#########.
...........
11 6
..#..#..#..
..#..#..#..
..#..#..###
..#..#..#@.
..#..#..#..
..#..#..#..
7 7
..#.#..
..#.#..
.###
...@...
.###
..#.#..
..#.#..
0 0


Output

45
59
6
13

### Response

```cpp
#include <cstdio>

char map[20][21];
int w, h;
int ans;
int x, y;
int xx, yy;
const int dx[4] = {0, 1, 0, -1}, dy[4] = {-1, 0, 1, 0};

void Move(int X, int Y) {
	ans++;
	map[Y][X] = '#';
	for(int i = 0; i < 4; i++) {
		xx = X + dx[i];
		yy = Y + dy[i];
		if(0 <= xx && xx < w && 0 <= yy && yy < h && map[yy][xx] == '.') {
			Move(xx, yy);
		}
	}
}

int main(void) {
	while(1) {
		ans = 0;
		scanf("%d %d", &w, &h);
		if(!w && !h) break;
		for(int i = 0; i < h; i++) {
			scanf("%s", map[i]);
			for(int j = 0; j < w; j++) {
				if(map[i][j] == '@') {
					x = j;
					y = i;
				}
			}
		}
		Move(x, y);
		printf("%d\n", ans);
	}
	return 0;
}
```