> #include<cstdio>
>  int dx[4]={0,0,-1,1};
>  int dy[4]={1,-1,0,0};
>  int temps,r,c;
>  char tiles[21][21];
>  void dfs(int x,int y)
>  {
>      int nx,ny;
>      temps++;
>      tiles[x][y]='#';
>      for(int i=0;i<4;i++)
>      {
>          nx=x+dx[i];
>          ny=y+dy[i];
>          if(nx>=1&&nx<=r&&ny>=1&&nx<=c&&tiles[nx][ny]=='.')
>             dfs(nx,ny);
>      }
>  }
>  int main()
>  {
>      int x,y;
>      while(scanf("%d%d",&c,&r)!=EOF&&r&&c)
>      {
>          for(int i=1;i<=r;i++)
>          {
>              getchar();
>              for(int j=1;j<=c;j++)
>              {
>                  scanf("%c",&tiles[i][j]);
>                  if(tiles[i][j]=='@')
>                     {
>                         x=i;
>                         y=j;
>                     }
>              }
>          }
>          temps=0;
>          dfs(x,y);
>          printf("%d\n",temps);
>      }
>      return 0;
>  }