#include 
#include 
#include 
using namespace std;

int main()
{
    int n, m;
    cin >> n >> m;
    
    char mat[n][m];
    int si, sj;
    int ei, ej;
    
    vector> dzidovi;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            cin >> mat[i][j];
            
            if(mat[i][j] == 'S') {
                si = i;
                sj = j;
            }
            if(mat[i][j] == 'E') {
                ei = i;
                ej = j;
            }
            if(mat[i][j] == '#') {
                dzidovi.push_back(make_pair(i, j));
            }
        }
    }
    
    int res = -1;
    
    int di[] = {-1, 1, 0, 0};
    int dj[] = {0, 0, -1, 1};
    
    for(int i = 0; i < dzidovi.size(); i++) {
        int qi = dzidovi[i].first, qj = dzidovi[i].second;
        mat[qi][qj] = '.';
        queue q;
        q.push(si);
        q.push(sj);
        q.push(0);
        vector> visited(n, vector(m, false));

        while(!q.empty()) {
            int ci = q.front();
            q.pop();
            int cj = q.front();
            q.pop();
            int dist = q.front();
            q.pop();
            
            if(ci == ei and cj == ej) {
                if(dist > res) {
                    res = dist;
                    break;
                }
            }
            
            for(int k = 0; k < 4; k++) {
                int ti = ci + di[k];
                int tj = cj + dj[k];
                
                if(ti >= 0 and ti < n and tj >= 0 and tj < m and !visited[ti][tj] and mat[ti][tj] != '#') {
                    q.push(ti);
                    q.push(tj);
                    q.push(dist + 1);
                    visited[ti][tj] = true;
                }
            }
        }
        mat[qi][qj] = '#';
    }
    cout << res << endl;
    
    
  
    return 0;

}