#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

#define RREP(i,s,e) for (int i = e-1; i >= s; i--)
#define rrep(i,n) RREP(i,0,n)
#define REP(i,s,e) for (int i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)

#define INF 1e8

int main() {
    int w, h;
    cin >> w >> h;
    vector<string> m;
    int square[h][w];
    m.resize(h);
    rep (i,h) {
        cin >> m[i];
        fill(square[i],square[i]+w,INF);
    }

    queue<tuple<int,int,int>> next;
    bool found = false;
    rep (i,h) rep (j,w) {
        if (!found && m[i][j] == '.') {
            found = true;
            queue<pair<int,int>> q;
            q.push(make_pair(i,j));
            next.push(make_tuple(i,j,0));
            while (!q.empty()) {
                int a, b;
                tie(a,b) = q.front();
                q.pop();
                if (m[a][b] == 'S')
                    continue;
                int x[4] = {-1, 0, 1, 0};
                rep (k,4) {
                    int u = a+x[k];
                    int v = b+x[(k+1)%4];
                    if (m[u][v] == '.') {
                        q.push(make_pair(u,v));
                        next.push(make_tuple(u,v,0));
                    }
                }
                m[a][b] = 'S';
            }
        }
    }
    int ans;
    while (!next.empty()) {
        int i, j, dis;
        tie(i,j,dis) = next.front();
        next.pop();
        if (m[i][j] == '.') {
            ans = dis - 1;
            break;
        }
        else if (square[i][j] == INF) {
            square[i][j] = dis;
            int x[4] = {-1, 0, 1, 0};
            rep (k,4) {
                int u = i+x[k];
                int v = j+x[(k+1)%4];
                if (0 <= u && u < h && 0 <= v && v < w && m[u][v] != 'S')
                    next.push(make_tuple(u,v,dis+1));
            }
        }
    }
    cout << ans << endl;
    return 0;
}