#include <bits/stdc++.h>
using namespace std;

int bfs(int si, int sj, int ei, int ej, int n, int m, vector<string>& grid) {
    vector<vector<bool>> visited(n, vector<bool>(m, false));
    queue<tuple<int, int, int>> q;
    q.push({si, sj, 0});
    visited[si][sj] = true;

    int di[] = {-1, 1, 0, 0};
    int dj[] = {0, 0, -1, 1};

    while (!q.empty()) {
        auto [ci, cj, dist] = q.front();
        q.pop();

        if (ci == ei && cj == ej) return dist;

        for (int k = 0; k < 4; k++) {
            int ni = ci + di[k];
            int nj = cj + dj[k];

            if (ni >= 0 && ni < n && nj >= 0 && nj < m && !visited[ni][nj] && grid[ni][nj] != '#') {
                visited[ni][nj] = true;
                q.push({ni, nj, dist + 1});
            }
        }
    }

    return -1;
}

int main() {
    int n, m;
    cin >> n >> m;
    vector<string> grid(n);
    for (int i = 0; i < n; i++) {
        cin >> grid[i];
    }

    int si = -1, sj = -1, ei = -1, ej = -1;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (grid[i][j] == 'S') {
                si = i;
                sj = j;
            } else if (grid[i][j] == 'E') {
                ei = i;
                ej = j;
            }
        }
    }

    int directPath = bfs(si, sj, ei, ej, n, m, grid);
    if (directPath != -1) {
        cout << directPath << endl;
        return 0;
    }


    int longestPathWithOneBlockRemoval = -1;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (grid[i][j] == '#') {

                grid[i][j] = '.';
                int pathWithRemoval = bfs(si, sj, ei, ej, n, m, grid);
                if (pathWithRemoval != -1) {
                    longestPathWithOneBlockRemoval = max(longestPathWithOneBlockRemoval, pathWithRemoval);
                }

                grid[i][j] = '#';
            }
        }
    }

    cout << longestPathWithOneBlockRemoval << endl;
    return 0;
}