#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    int W,H; cin >> W >> H;
    vector<string> C(H);
    rep(i,H) cin >> C[i];

    vector<pair<int,int>> S, T;
    int di[] = {0, 1, 0, -1};
    int dj[] = {1, 0, -1, 0};
    auto f = [&](vector<pair<int,int>> &V, char X) {
        rep(i,H)rep(j,W) if(C[i][j] == '.') {
            queue<pair<int,int>> q;
            q.push({i, j});
            V.push_back({i, j});
            C[i][j] = X;
            while(!q.empty()) {
                auto [ci, cj] = q.front(); q.pop();
                rep(d,4) {
                    int ni = ci + di[d], nj = cj + dj[d];
                    if(0 <= ni && ni < H && 0 <= nj && nj < W && C[ni][nj] == '.') {
                        C[ni][nj] = X;
                        V.push_back({ni, nj});
                        q.push({ni, nj});
                    }
                }
            }
            return;
        }
    };

    f(S, 'S');
    f(T, 'T');
    int ans = 1e9;
    for(auto [si, sj] : S) for(auto [ti, tj] : T) ans = min(ans, abs(si - ti) + abs(sj - tj));
    cout << ans - 1 << endl;
}