#include<cstdio>
#include<iostream>

using namespace std;

#define HMAX 20
#define WMAX 20

char room[HMAX+5][WMAX+5];
int W,H;

typedef struct{
	int x;
	int y;
}map;

int solve(int x,int y){
	int dx[4]={ 0, 0, 1,-1};
	int dy[4]={ 1,-1, 0, 0};
	int cnt=0;

	room[y][x]='#';
	
	for(int i=0;i<4;i++){
		if(x+dx[i]>=0&&x+dx[i]<W&&y+dy[i]>=0&&y+dy[i]<H){
			if(room[y+dy[i]][x+dx[i]]=='.'){
				cnt+=solve(x+dx[i],y+dy[i]);
			}
		}
	}

	return cnt+1;
}

int main(void){

	map start;

	while(1){
		cin>>W>>H;
		if(W==0&&H==0) break;
		for(int i=0;i<H;i++){
			for(int j=0;j<W;j++){
				cin>>room[i][j];
				if(room[i][j]=='@') start.x=j,start.y=i;
			}
		}
		cout<<solve(start.x,start.y)<<endl;
	}
	
	return 0;
}
### Prompt

Please formulate a cpp solution to 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<cstdio>
#include<iostream>

using namespace std;

#define HMAX 20
#define WMAX 20

char room[HMAX+5][WMAX+5];
int W,H;

typedef struct{
	int x;
	int y;
}map;

int solve(int x,int y){
	int dx[4]={ 0, 0, 1,-1};
	int dy[4]={ 1,-1, 0, 0};
	int cnt=0;

	room[y][x]='#';
	
	for(int i=0;i<4;i++){
		if(x+dx[i]>=0&&x+dx[i]<W&&y+dy[i]>=0&&y+dy[i]<H){
			if(room[y+dy[i]][x+dx[i]]=='.'){
				cnt+=solve(x+dx[i],y+dy[i]);
			}
		}
	}

	return cnt+1;
}

int main(void){

	map start;

	while(1){
		cin>>W>>H;
		if(W==0&&H==0) break;
		for(int i=0;i<H;i++){
			for(int j=0;j<W;j++){
				cin>>room[i][j];
				if(room[i][j]=='@') start.x=j,start.y=i;
			}
		}
		cout<<solve(start.x,start.y)<<endl;
	}
	
	return 0;
}
```