#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef double ld;
//#define ll __int128
#define int ll
//#dLefine char ll
//#define double ld
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef MAX_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";


template<class T0, class T1>
inline ostream &operator<<(ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template<class T0, class T1>
inline istream &operator>>(istream &in, pair<T0, T1> &a) {
    return in >> a.first >> a.second;
}

template<class T0, class T1, class T2>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template<class T0, class T1, class T2, class T3>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " << get<3>(a) << "}";
}

template<class T>
inline ostream &operator<<(ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}


void smain();


signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
#ifdef MAX_HOME
    freopen("input.txt", "r", stdin);
    clock_t start = clock();
#endif
#ifdef HK_CUP
    freopen("finput.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    cout << setprecision(12) << fixed;
    smain();
#ifdef MAX_HOME
#ifndef HK_CUP
    cout << "\n\nTOTAL EXECUTION TIME: " << float(clock() - start) / CLOCKS_PER_SEC << endl;
#endif
#endif
    return 0;
}


const ll oo = 1e12 + 10;

template <int N>
struct Mcmf {
    struct edge {
        int from, to, flow, cap, cost;
    };
    vector<edge> e;
    vi g[N];

    inline void add_edge(int from, int to, int cap, int cost) {
//        cout << from << " , " << to << " = (" << cap << ", " << cost << ")" << endl;
        g[from].push_back(e.size());
        e.push_back({from, to, 0, cap, cost});
        g[to].push_back(e.size());
        e.push_back({to, from, 0, 0, -cost});
    }

    int d[N];
    bool in_que[N];
    int from[N];

    pii mcmf(int s, int t) {
        int flow = 0, cost = 0;
        while (1) {
            fill(d, d + t + 1, oo);
            fill(in_que, in_que + t + 1, 0);
            d[s] = 0;
            in_que[s] = 1;
            queue<int> q;
            q.push(s);
            while (!q.empty()) {
                int v = q.front();
                q.pop();
                in_que[v] = 0;
                for (int id : g[v]) {
                    int to = e[id].to;
                    if (e[id].cap > e[id].flow && d[to] > d[v] + e[id].cost) {
                        d[to] = d[v] + e[id].cost;
                        from[to] = id;
                        if (!in_que[to]) {
                            q.push(to);
                            in_que[to] = 1;
                        }
                    }
                }
            }
            if (d[t] == oo) break;
            int v = t;
            vi ids;
            int pushed = oo;
            while (v != s) {
                int id = from[v];
                ids.push_back(id);
                v = e[id].from;
                inmin(pushed, e[id].cap - e[id].flow);
            }
            flow += pushed;
            for (auto id : ids) {
                e[id].flow += pushed;
                e[id ^ 1].flow -= pushed;
                cost += pushed * e[id].cost;
            }
        }
        return {flow, cost};
    };
};


const int oosmall = 1e6 + 10;
const int N = 55;

string mat[N];

const int S = 1e4 + 10;

void smain() {

    int n, m;
    cin >> n >> m;
    fori (i, n) {
        cin >> mat[i];
    }
    Mcmf<S> mcmf;

    int s = n * m;
    int t = s + 1;
    int cnt0 = 0;
    fori (i, n) {
        fori (j, m) {
            mcmf.add_edge(i * m + j, t, 1, 0);
            if (mat[i][j] == 'o') {
                cnt0++;
                mcmf.add_edge(s, i * m + j, 1, -oosmall);
            }
            if (i + 1 != n && mat[i][j] != '#' && mat[i + 1][j] != '#') {
                mcmf.add_edge(i * m + j, (i + 1) * m + j, oosmall, -1);
            }
            if (j + 1 != m && mat[i][j] != '#' && mat[i][j + 1] != '#') {
                mcmf.add_edge(i * m + j, i * m + j + 1, oosmall, -1);
            }
        }
    }

    pii ans = mcmf.mcmf(s, t);
    watch(ans);
    cout << -(ans.second + oosmall * cnt0);
}

Measured memory_bytes: 4408