#include <iostream>
#include <algorithm>
#include <utility>

using namespace std;

char board[23 * 23];
int way[4] = { -1,1,-23,23 };
int gCount;

void solve(int pos) {
	gCount++;
	board[pos] = '#';
	for (int i = 0; i < 4; i++) 
		if (board[pos + way[i]] == '.') 
			solve(pos + way[i]);
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int H, W;
	while (cin >> W >> H, W) {
		for (int i = 0; i < 23 * 23; i++)
			board[i] = '#';
		gCount = 0;
		int s;
		for (int y = 1; y <= H; y++)
			for (int x = 1; x <= W; x++) {
				cin >> board[y * 23 + x];
				if (board[y * 23 + x] == '@') 
					s = y * 23 + x;
			}
		solve(s);
		cout << gCount << endl;
	}
}
### Prompt

In Cpp, your task is to solve the following problem:

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 <iostream>
#include <algorithm>
#include <utility>

using namespace std;

char board[23 * 23];
int way[4] = { -1,1,-23,23 };
int gCount;

void solve(int pos) {
	gCount++;
	board[pos] = '#';
	for (int i = 0; i < 4; i++) 
		if (board[pos + way[i]] == '.') 
			solve(pos + way[i]);
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int H, W;
	while (cin >> W >> H, W) {
		for (int i = 0; i < 23 * 23; i++)
			board[i] = '#';
		gCount = 0;
		int s;
		for (int y = 1; y <= H; y++)
			for (int x = 1; x <= W; x++) {
				cin >> board[y * 23 + x];
				if (board[y * 23 + x] == '@') 
					s = y * 23 + x;
			}
		solve(s);
		cout << gCount << endl;
	}
}
```