#include<iostream>
#include<cstring>
#include<queue>
using namespace std;
int m, n;
const int MAX = 301;
int a = 0, b = 0;
bool used[MAX][MAX];
char maze[MAX][MAX];
struct point
{
    int x, y;
    int d;
    point(int x1, int y1, int d1) :x(x1), y(y1), d(d1)
    {}
};

int bfs();
int main()
{
    int i, j;
    while (cin >> m >> n)
    {


        memset(used, false, sizeof(used));
        if (m == 0 && n == 0)
            break;
        for (i = 1; i <= m; i++)
            for (j = 1; j <= n; j++)
            {
                cin >> maze[i][j];
                if (maze[i][j] == '@')
                {
                    a = i;
                    b = j;
                }
            }
        cout << bfs() << endl;
    }
    return 0;
}


int bfs()
{
    queue<point> q;
    q.push(point(a, b, 0));
    used[a][b] = true;
    while (!q.empty())
    {
        point p = q.front();
        q.pop();
        if (maze[p.x][p.y] == '*')
            return p.d;
        else
        {
            if (p.x - 1 >= 1 && maze[p.x - 1][p.y] != '#' && !used[p.x - 1][p.y])
            {
                used[p.x - 1][p.y] = true;
                q.push(point(p.x - 1, p.y, p.d + 1));
            }

            if (p.x + 1 <= m && maze[p.x + 1][p.y] != '#' && !used[p.x + 1][p.y])
            {
                used[p.x + 1][p.y] = true;
                q.push(point(p.x + 1, p.y, p.d + 1));
            }

            if (p.y - 1 >= 1 && maze[p.x][p.y - 1] != '#' && !used[p.x][p.y - 1])
            {
                used[p.x][p.y - 1] = true;
                q.push(point(p.x, p.y - 1, p.d + 1));
            }

            if (p.y + 1 <= n && maze[p.x][p.y + 1] != '#' && !used[p.x][p.y + 1])
            {
                used[p.x][p.y + 1] = true;
                q.push(point(p.x, p.y + 1, p.d + 1));
            }
        }
    }
    return -1;
}