#include <iostream>
#include <vector>
using namespace std;
int solve(bool visited[20][20],vector<string> v,int x,int y,int w,int h){
	if(x<0||y<0||w<=x||h<=y) return 0;
	if(visited[y][x]==true||v[y][x]=='#') return 0;
	int sum=1;
	visited[y][x]=true;
	sum+=solve(visited,v,x+1,y,w,h);
	sum+=solve(visited,v,x,y+1,w,h);
	sum+=solve(visited,v,x-1,y,w,h);
	sum+=solve(visited,v,x,y-1,w,h);
	return sum;
}
int main(void){
	int w,h;
	while(cin>>w>>h,w||h){
		vector<string> v;
		bool visited[20][20];
		for(int i=0;i<20;++i) for(int j=0;j<20;++j)visited[i][j]=false;
		int x,y;
		for(int i=0;i<h;++i){
			string s;cin>>s;
			if(s.find("@")!=-1){x=s.find("@");y=i;}
			v.push_back(s);
		}
		cout<<solve(visited,v,x,y,w,h)<<endl;
	}
	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 <iostream>
#include <vector>
using namespace std;
int solve(bool visited[20][20],vector<string> v,int x,int y,int w,int h){
	if(x<0||y<0||w<=x||h<=y) return 0;
	if(visited[y][x]==true||v[y][x]=='#') return 0;
	int sum=1;
	visited[y][x]=true;
	sum+=solve(visited,v,x+1,y,w,h);
	sum+=solve(visited,v,x,y+1,w,h);
	sum+=solve(visited,v,x-1,y,w,h);
	sum+=solve(visited,v,x,y-1,w,h);
	return sum;
}
int main(void){
	int w,h;
	while(cin>>w>>h,w||h){
		vector<string> v;
		bool visited[20][20];
		for(int i=0;i<20;++i) for(int j=0;j<20;++j)visited[i][j]=false;
		int x,y;
		for(int i=0;i<h;++i){
			string s;cin>>s;
			if(s.find("@")!=-1){x=s.find("@");y=i;}
			v.push_back(s);
		}
		cout<<solve(visited,v,x,y,w,h)<<endl;
	}
	return 0;
}
```