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

#define int long long
#define double long double
#define rep(i, n) for (int i = 0; i < (n); i++)
#define reps(i, n) for (int i = 1; i <= (n); i++)
#define all(x) (x).begin(), (x).end()
#define uniq(x) (x).erase(unique(all(x)), (x).end())
#define bit(n) (1LL << (n))
#define dump(x) cerr << #x " = " << (x) << endl
using vint=vector<int>;
using vvint=vector<vint>;
using pint=pair<int, int>;
using vpint=vector<pint>;
template<typename T> using priority_queue_rev=priority_queue<T, vector<T>, greater<T>>;
constexpr double pi = 3.1415926535897932384626433832795028;
constexpr int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
constexpr int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int gcd(int a, int b) {
    while (b) { swap(a %= b, b); }
    return a;
}
int lcm(int a, int b) { return a / gcd(a, b) * b; }
template<typename T1, typename T2> bool chmax(T1 &a, const T2 &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template<typename T1, typename T2> bool chmin(T1 &a, const T2 &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &rhs) {
    os << "(" << rhs.first << ", " << rhs.second << ")";
    return os;
}
template<typename T> ostream &operator<<(ostream &os, const vector<T> &rhs) {
    os << "{";
    for (auto itr = rhs.begin(); itr != rhs.end(); itr++) {
        os << *itr << (next(itr) != rhs.end() ? ", " : "");
    }
    os << "}";
    return os;
}
struct Setup {
    static constexpr int PREC = 20;
    Setup() {
        cout << fixed << setprecision(PREC);
        cerr << fixed << setprecision(PREC);
    };
} setup;

template<typename T>
struct Dinic {
    struct edge {
        int to, rev;
        T cap;
        bool isRev;
    };
    int n;
    T ZERO, INF;
    std::vector<std::vector<edge>> G;
    std::vector<int> level, iter;
    Dinic(int n, T INF = std::numeric_limits<T>::max(), T ZERO = T())
        : n(n), INF(INF), ZERO(ZERO), G(n), level(n), iter(n) {}
    void addEdge(int from, int to, T cap) {
        G[from].push_back({to, (int) G[to].size(), cap, false});
        G[to].push_back({from, (int) G[from].size() - 1, ZERO, true});
    }
    void bfs(int s) {
        fill(level.begin(), level.end(), -1);
        std::queue<int> que;
        level[s] = 0;
        que.push(s);
        while (!que.empty()) {
            int v = que.front();
            que.pop();
            for (int i = 0; i < G[v].size(); i++) {
                edge &e = G[v][i];
                if (e.cap > ZERO && level[e.to] < 0) {
                    level[e.to] = level[v] + 1;
                    que.push(e.to);
                }
            }
        }
    }
    T dfs(int v, int t, T f) {
        if (v == t) { return f; }
        for (int &i = iter[v]; i < G[v].size(); i++) {
            edge &e = G[v][i];
            if (level[v] < level[e.to] && e.cap > ZERO) {
                T d = dfs(e.to, t, std::min(f, e.cap));
                if (d > ZERO) {
                    e.cap -= d;
                    G[e.to][e.rev].cap += d;
                    return d;
                }
            }
        }
        return ZERO;
    }
    T calcMaxFlow(int s, int t, T lim) {
        T flow = ZERO;
        while (true) {
            bfs(s);
            if (level[t] < 0 || lim == ZERO) { return flow; }
            fill(iter.begin(), iter.end(), 0);
            T f;
            while ((f = dfs(s, t, lim)) > ZERO) {
                flow += f;
                lim -= f;
            }
        }
    }
    T calcMaxFlow(int s, int t) { return calcMaxFlow(s, t, INF); }
    std::map<std::pair<int, int>, T> getMaxFlow() {
        std::map<std::pair<int, int>, T> ret;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < G[i].size(); j++) {
                edge &e = G[i][j];
                if (e.isRev) { ret[{e.to, i}] = e.cap; }
            }
        }
        return ret;
    }
    std::map<std::pair<int, int>, T> getMinCut(int s) {
        std::map<std::pair<int, int>, T> ret;
        std::vector<int> visited(n);
        std::queue<int> que;
        que.push(s);
        while (!que.empty()) {
            int v = que.front();
            que.pop();
            if (visited[v]) { continue; }
            visited[v] = true;
            for (int i = 0; i < G[v].size(); i++) {
                edge &e = G[v][i];
                if (e.cap > ZERO) { que.push(e.to); }
            }
        }
        for (int i = 0; i < n; i++) {
            if (visited[i]) { continue; }
            for (int j = 0; j < G[i].size(); j++) {
                edge &e = G[i][j];
                if (e.isRev && visited[e.to]) { ret[{e.to, i}] = e.cap; }
            }
        }
        return ret;
    }
};

int H, W;
string a[110];
signed main() {
    cin >> H >> W;
    rep(i, H) { cin >> a[i]; }
    Dinic<int> dnc(H * W * 2);
    int s, t;
    int INF = 114514;
    rep(i, H) {
        rep(j, W) {
            int cur0 = (i * W + j) * 2, cur1 = cur0 + 1;
            int cap = INF;
            if (a[i][j] == 'S') { s = cur0; }
            if (a[i][j] == 'T') { t = cur1; }
            if (a[i][j] == 'o') { cap = 1; }
            if (a[i][j] == '.') { cap = 0; }
            dnc.addEdge(cur0, cur1, cap);
            rep(k, H) {
                if (i != k) { dnc.addEdge(cur1, (k * W + j) * 2, INF); }
            }
            rep(k, W) {
                if (j != k) { dnc.addEdge(cur1, (i * W + k) * 2, INF); }
            }
        }
    }
    int ans = dnc.calcMaxFlow(s, t);
    cout << (ans < INF ? ans : -1) << endl;
}

Measured memory_bytes: 165632