#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using namespace std;
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define rep(i, n) rep2(i, 0, n)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define drep(i, n) drep2(i, n, 0)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#ifdef LOCAL
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) { cerr << ' ' << H; debug_out(T...); }
#define debug(...) cerr << 'L' << __LINE__ << " [" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define dump(x) cerr << 'L' << __LINE__ << " " << #x << " = " << (x) << endl
#else
#define debug(...) (void(0))
#define dump(x) (void(0))
#endif
template<typename T> using V = vector<T>;
template<typename T> using P = pair<T, T>;
using ll = long long;
using ld = long double;
using Vi = V<int>;  using VVi = V<Vi>;
using Vl = V<ll>;   using VVl = V<Vl>;
using Vd = V<ld>;   using VVd = V<Vd>;
using Vb = V<bool>; using VVb = V<Vb>;
using Pi = P<int>;
using Pl = P<ll>;
using Pd = P<ld>;
template<typename T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
template<typename T> vector<T> make_vec(size_t n, T a) { return vector<T>(n, a); }
template<typename... Ts> auto make_vec(size_t n, Ts... ts) { return vector<decltype(make_vec(ts...))>(n, make_vec(ts...)); }
template<typename T> inline int sz(T &x) { return x.size(); }
template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }
template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
template<typename T1, typename T2> istream &operator>>(istream &is, pair<T1, T2> &p) { is >> p.first >> p.second; return is; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p) { os << '(' << p.first << ", " << p.second << ')'; return os; }
template<typename T> istream &operator>>(istream &is, vector<T> &v) { for (auto &e : v) is >> e; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << ' '; return os; }
template<typename T> inline int count_between(vector<T> &a, T l, T r) { return lower_bound(all(a), r) - lower_bound(all(a), l); } // [l, r)
inline ll cDiv(const ll x, const ll y) { return (x+y-1) / y; } // ceil(x/y)
inline int fLog2(const ll x) { assert(x > 0); return 63-__builtin_clzll(x); } // floor(log2(x))
inline int cLog2(const ll x) { assert(x > 0); return (x == 1) ? 0 : 64-__builtin_clzll(x-1); } // ceil(log2(x))
inline int popcount(const ll x) { return __builtin_popcountll(x); }
inline void fail() { cout << -1 << '\n'; exit(0); }
struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
// const int INF  = 1<<30;
// const ll INFll = 1ll<<60;
// const ld EPS   = 1e-10;
// const ld PI    = acos(-1.0);
// const int MOD  = int(1e9)+7;
// const int MOD  = 998244353;



template<typename CapType, typename CostType> class MinCostFlowDAG {
public:
    using Cat = CapType;
    using Cot = CostType;
    using pti = pair<Cot, int>;
    struct edge {
        int to, rev;
        Cat cap;
        Cot cost;
    };
    const int V;
    const Cot inf;
    vector<vector<edge> > G;
    vector<Cot> h, dist;
    vector<int> deg, ord, prevv, preve;
    MinCostFlowDAG(const int node_size) : V(node_size), inf(numeric_limits<Cot>::max()),
        G(V), h(V, inf), dist(V), deg(V, 0), prevv(V), preve(V){}
    void add_edge(const int from, const int to, const Cat cap, const Cot cost){
        if(cap == 0) return;
        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});
        ++deg[to];
    }
    bool tsort(){
        queue<int> que;
        for(int i = 0; i < V; ++i){
            if(deg[i] == 0) que.push(i);
        }
        while(!que.empty()){
            const int p = que.front();
            que.pop();
            ord.push_back(p);
            for(auto& e : G[p]){
                if(e.cap > 0 && --deg[e.to] == 0) que.push(e.to);
            }
        }
        return (*max_element(deg.begin(), deg.end()) == 0);
    }
    void calc_potential(const int s){
        h[s] = 0;
        for(const int v : ord){
            if(h[v] == inf) continue;
            for(const edge& e : G[v]){
                if(e.cap > 0) h[e.to] = min(h[e.to], h[v] + e.cost);
            }
        }
    }
    void Dijkstra(const int s){
        priority_queue<pti,vector<pti>,greater<pti> > que;
        fill(dist.begin(), dist.end(), inf);
        dist[s] = 0;
        que.push(pti(0, s));
        while(!que.empty()){
            pti p = que.top();
            que.pop();
            const int v = p.second;
            if(dist[v] < p.first) continue;
            for(int i = 0; i < (int)G[v].size(); ++i){
                edge& e = G[v][i];
                if(e.cap > 0 && dist[e.to] > dist[v] + e.cost + h[v] - h[e.to]){
                    dist[e.to] = dist[v] + e.cost + h[v] - h[e.to];
                    prevv[e.to] = v, preve[e.to] = i;
                    que.push(pti(dist[e.to], e.to));
                }
            }
        }
    }
    void update(const int s, const int t, Cat& f, Cot& res){
        for(int i = 0; i < V; i++){
            if(dist[i] != inf) h[i] += dist[i];
        }
        Cat d = f;
        for(int v = t; v != s; v = prevv[v]){
            d = min(d, G[prevv[v]][preve[v]].cap);
        }
        f -= d;
        res += h[t] * d;
        for(int v = t; v != s; v = prevv[v]){
            edge& e = G[prevv[v]][preve[v]];
            e.cap -= d;
            G[v][e.rev].cap += d;
        }
    }
    Cot solve(const int s, const int t, Cat f){
        if(!tsort()) assert(false); // not DAG
        calc_potential(s);
        Cot res = 0;
        while(f > 0){
            Dijkstra(s);
            if(dist[t] == inf) return -inf;
            update(s, t, f, res);
        }
        return res;
    }
};


const array<int, 2> di = {1, 0};
const array<int, 2> dj = {0, 1};

int main() {
  int n, m; cin >> n >> m;
  V<string> S(n); cin >> S;
  int s = n*m;
  int t = s+1;
  int N = n*m + 2;


  auto uid = [&] (int i, int j) {
    return i * m + j;
  };


  MinCostFlowDAG<int, int> mcf(N);

  int cnt = 0;
 
  rep(i, n) rep(j, m) {
    rep(d, sz(di)) {
      int i2 = i + di[d];
      int j2 = j + dj[d];
      if (i2 < 0 || i2 >= n || j2 < 0 || j2 >= m) continue;
      if (S[i][j] == '#') continue;
      if (S[i2][j2] == '#') continue;
      mcf.add_edge(uid(i, j), uid(i2, j2), 100, -1);
    }

    if (S[i][j] == 'o') mcf.add_edge(s, uid(i, j), 1, 0);
    if (S[i][j] == 'o') ++cnt;
    if (S[i][j] != '#') mcf.add_edge(uid(i, j), t, 1, 0);
  }


  ll ans = -mcf.solve(s, t, cnt);

  cout << ans << '\n';
}


Measured memory_bytes: 4184