#include <iostream>
#include <algorithm>
#include <cassert>
#include <limits>
#include <queue>
#include <vector>

using namespace std;

template <class Cap, class Cost> struct mcf_graph {
  public:
    mcf_graph() {}
    mcf_graph(int n) : _n(n), g(n) {}

    int add_edge(int from, int to, Cap cap, Cost cost) {
        assert(0 <= from && from < _n);
        assert(0 <= to && to < _n);
        int m = int(pos.size());
        pos.push_back({from, int(g[from].size())});
        g[from].push_back(_edge{to, int(g[to].size()), cap, cost});
        g[to].push_back(_edge{from, int(g[from].size()) - 1, 0, -cost});
        return m;
    }

    struct edge {
        int from, to;
        Cap cap, flow;
        Cost cost;
    };

    edge get_edge(int i) {
        int m = int(pos.size());
        assert(0 <= i && i < m);
        auto _e = g[pos[i].first][pos[i].second];
        auto _re = g[_e.to][_e.rev];
        return edge{
            pos[i].first, _e.to, _e.cap + _re.cap, _re.cap, _e.cost,
        };
    }
    std::vector<edge> edges() {
        int m = int(pos.size());
        std::vector<edge> result(m);
        for (int i = 0; i < m; i++) {
            result[i] = get_edge(i);
        }
        return result;
    }

    std::pair<Cap, Cost> flow(int s, int t) {
        return flow(s, t, std::numeric_limits<Cap>::max());
    }
    std::pair<Cap, Cost> flow(int s, int t, Cap flow_limit) {
        return slope(s, t, flow_limit).back();
    }
    std::vector<std::pair<Cap, Cost>> slope(int s, int t) {
        return slope(s, t, std::numeric_limits<Cap>::max());
    }
    std::vector<std::pair<Cap, Cost>> slope(int s, int t, Cap flow_limit) {
        assert(0 <= s && s < _n);
        assert(0 <= t && t < _n);
        assert(s != t);
        // variants (C = maxcost):
        // -(n-1)C <= dual[s] <= dual[i] <= dual[t] = 0
        // reduced cost (= e.cost + dual[e.from] - dual[e.to]) >= 0 for all edge
        std::vector<Cost> dual(_n, 0), dist(_n);
        std::vector<int> pv(_n), pe(_n);
        std::vector<bool> vis(_n);
        auto dual_ref = [&]() {
            std::fill(dist.begin(), dist.end(),
                      std::numeric_limits<Cost>::max());
            std::fill(pv.begin(), pv.end(), -1);
            std::fill(pe.begin(), pe.end(), -1);
            std::fill(vis.begin(), vis.end(), false);
            struct Q {
                Cost key;
                int to;
                bool operator<(Q r) const { return key > r.key; }
            };
            std::priority_queue<Q> que;
            dist[s] = 0;
            que.push(Q{0, s});
            while (!que.empty()) {
                int v = que.top().to;
                que.pop();
                if (vis[v]) continue;
                vis[v] = true;
                if (v == t) break;
                // dist[v] = shortest(s, v) + dual[s] - dual[v]
                // dist[v] >= 0 (all reduced cost are positive)
                // dist[v] <= (n-1)C
                for (int i = 0; i < int(g[v].size()); i++) {
                    auto e = g[v][i];
                    if (vis[e.to] || !e.cap) continue;
                    // |-dual[e.to] + dual[v]| <= (n-1)C
                    // cost <= C - -(n-1)C + 0 = nC
                    Cost cost = e.cost - dual[e.to] + dual[v];
                    if (dist[e.to] - dist[v] > cost) {
                        dist[e.to] = dist[v] + cost;
                        pv[e.to] = v;
                        pe[e.to] = i;
                        que.push(Q{dist[e.to], e.to});
                    }
                }
            }
            if (!vis[t]) {
                return false;
            }

            for (int v = 0; v < _n; v++) {
                if (!vis[v]) continue;
                // dual[v] = dual[v] - dist[t] + dist[v]
                //         = dual[v] - (shortest(s, t) + dual[s] - dual[t]) + (shortest(s, v) + dual[s] - dual[v])
                //         = - shortest(s, t) + dual[t] + shortest(s, v)
                //         = shortest(s, v) - shortest(s, t) >= 0 - (n-1)C
                dual[v] -= dist[t] - dist[v];
            }
            return true;
        };
        Cap flow = 0;
        Cost cost = 0, prev_cost = -1;
        std::vector<std::pair<Cap, Cost>> result;
        result.push_back({flow, cost});
        while (flow < flow_limit) {
            if (!dual_ref()) break;
            Cap c = flow_limit - flow;
            for (int v = t; v != s; v = pv[v]) {
                c = std::min(c, g[pv[v]][pe[v]].cap);
            }
            for (int v = t; v != s; v = pv[v]) {
                auto& e = g[pv[v]][pe[v]];
                e.cap -= c;
                g[v][e.rev].cap += c;
            }
            Cost d = -dual[s];
            flow += c;
            cost += c * d;
            if (prev_cost == d) {
                result.pop_back();
            }
            result.push_back({flow, cost});
            prev_cost = cost;
        }
        return result;
    }

  private:
    int _n;

    struct _edge {
        int to, rev;
        Cap cap;
        Cost cost;
    };

    std::vector<std::pair<int, int>> pos;
    std::vector<std::vector<_edge>> g;
};


const long long BIG = 1'000'000'000;

void print(int index, int n, int m) {
    int type = index / (n * m);
    index %= (n * m);
    int i = index / m;
    int j = index % m;
    printf("(%d, %d, %d)", type, i, j);
}

int main() {
    int n, m;
    cin >> n >> m;

    string ss[n];
    for (int i = 0; i < n; i++) {
        cin >> ss[i];
    }
    mcf_graph<int, int> g(2 * n * m + 2);

    int count_source = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (ss[i][j] == 'o') {
                count_source++;
                bool map[n][m];
                map[i][j] = true;
                g.add_edge(2 * n * m, i * m + j, 1, 0);
                for (int a = i; a < n; a++) {
                    for (int b = j; b < m; b++) {
//                        printf("i: %d, j: %d, a: %d, b: %d\n", i, j, a, b);
                        if (ss[a][b] == '#') {
//                            printf("skip\n");
                            continue;
                        }
                        map[a][b] = (i == a && j == b);
                        if (a > i && ss[a - 1][b] != '#') {
                            map[a][b] |= map[a - 1][b];
                        }
                        if (b > j && ss[a][b - 1] != '#') {
                            map[a][b] |= map[a][b - 1];
                        }
                        if (map[a][b]) {
//                            printf("add edge\n");
                            g.add_edge(i * m + j, n * m + a * m + b, 1, n + m - (a - i) - (b - j));
                        } else {
//                            printf("no edge\n");

                        }
                    }
                }
            }
            if (ss[i][j] != '#') {
                g.add_edge(n * m + i * m + j, 2 * n * m + 1, 1, 0);
            }
        }
    }
    auto result = g.flow(2 * n * m, 2 * n * m + 1, count_source);
    cout << count_source * (n + m) - result.second << endl;
    auto edges = g.edges();
    /*
    for (auto edge : edges) {
        print(edge.from, n, m);
        printf(" - ");
        print(edge.to, n, m);
        printf(" - ");
        printf("%d, %d\n", edge.flow, edge.cost);
    }
    */
/*
    int s = 2 * n, t = 2 * n + 1;

    // we can "waste" the flow
    g.add_edge(s, t, n * k, BIG);

    for (int i = 0; i < n; i++) {
        g.add_edge(s, i, k, 0);
        g.add_edge(n + i, t, k, 0);
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            long long a;
            cin >> a;
            g.add_edge(i, n + j, 1, BIG - a);
        }
    }

    auto result = g.flow(s, t, n * k);
    cout << 1LL * n * k * BIG - result.second << endl;

    vector<string> grid(n, string(n, '.'));
    auto edges = g.edges();
    for (auto e : edges) {
        if (e.from == s || e.to == t || e.flow == 0) continue;

        grid[e.from][e.to - n] = 'X';
    }

    for (int i = 0; i < n; i++) {
        cout << grid[i] << endl;
    }
    return 0;
    */
}


Measured memory_bytes: 8468