#line 2 "header.hpp"

//%snippet.set('header')%
//%snippet.fold()%
#ifndef HEADER_H
#define HEADER_H

// template version 2.0
using namespace std;
#include <bits/stdc++.h>

// varibable settings
const long long INF = 1e18;
template <class T> constexpr T inf = numeric_limits<T>::max() / 2.1;

#define _overload3(_1, _2, _3, name, ...) name
#define _rep(i, n) repi(i, 0, n)
#define repi(i, a, b) for (ll i = (ll)(a); i < (ll)(b); ++i)
#define rep(...) _overload3(__VA_ARGS__, repi, _rep, )(__VA_ARGS__)
#define _rrep(i, n) rrepi(i, 0, n)
#define rrepi(i, a, b) for (ll i = (ll)((b)-1); i >= (ll)(a); --i)
#define r_rep(...) _overload3(__VA_ARGS__, rrepi, _rrep, )(__VA_ARGS__)
#define each(i, a) for (auto &&i : a)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b)
#define mt(...) make_tuple(__VA_ARGS__)
#define ub upper_bound
#define lb lower_bound
#define lpos(A, x) (lower_bound(all(A), x) - A.begin())
#define upos(A, x) (upper_bound(all(A), x) - A.begin())
template <class T, class U> inline void chmax(T &a, const U &b) { if ((a) < (b)) (a) = (b); }
template <class T, class U> inline void chmin(T &a, const U &b) { if ((a) > (b)) (a) = (b); }
template <typename X, typename T> auto make_table(X x, T a) { return vector<T>(x, a); }
template <typename X, typename Y, typename Z, typename... Zs> auto make_table(X x, Y y, Z z, Zs... zs) { auto cont = make_table(y, z, zs...); return vector<decltype(cont)>(x, cont); }

#define cdiv(a, b) (((a) + (b)-1) / (b))
#define is_in(x, a, b) ((a) <= (x) && (x) < (b))
#define uni(x) sort(all(x)); x.erase(unique(all(x)), x.end())
#define slice(l, r) substr(l, r - l)

typedef long long ll;
typedef long double ld;
using vl = vector<ll>;
using vvl = vector<vl>;
using pll = pair<ll, ll>;

template <typename T>
using PQ = priority_queue<T, vector<T>, greater<T>>;
void check_input() { assert(cin.eof() == 0); int tmp; cin >> tmp; assert(cin.eof() == 1); }

#if defined(PCM) || defined(LOCAL)
#else
#define dump(...) ;
#define dump_1d(...) ;
#define dump_2d(...) ;
#define cerrendl ;
#endif

#endif /* HEADER_H */
//%snippet.end()%
#line 2 "solve.cpp"
template<class T=ll> using vec = vector<T>;
struct Fast { Fast() { std::cin.tie(0); ios::sync_with_stdio(false); } } fast;

#include <atcoder/mincostflow>
using namespace atcoder;

int solve() {
    ll h,w;cin>>h>>w;
    ll n = h*w;
    vec<string> s(h);
    rep(i, h) cin>>s[i];
    auto nid = [&](ll i, ll j, ll k){return (i*w*2 + j*2 + k);};
    auto pos = [&](ll u) -> tuple<ll, ll, ll> { 
        ll i = u/(w*2);
        ll j = u / 2 % w;
        ll k = u % 2;
        return {i, j, k};
    };
    ll ans = 0;
    mcf_graph<int, long long> g(2 * n + 2);
    int start = 2 * n, target = 2 * n + 1;

    ll cnt = 0;
    rep(i, h){
        rep(j, w){
            if (s[i][j] == '.'){
                g.add_edge(nid(i, j, 1), target, 1, 0);
            }
            else if (s[i][j] == 'o'){
                ans -= (i+j);
                g.add_edge(start, nid(i, j, 0), 1, 0);
                g.add_edge(nid(i, j, 0), nid(i, j, 1), 1, 1000-(i+j));
                g.add_edge(nid(i, j, 1), target, 1, 0);
                cnt++;
                stack<pll> st;
                st.push(mp(nid(i, j, 0), 0));
                vvl used = make_table(h, w, 0LL);
                used[i][j] = 1;
                while(sz(st)>0){
                    auto [ij, dist] = st.top();st.pop();
                    auto [x, y, _] = pos(ij);
                    auto update = [&](auto nx, auto ny){
                        if (0 <= nx && nx < h && 0 <= ny && ny < w){
                            if (s[nx][ny] != '#' && used[nx][ny] == 0){
                                st.push(mp(nid(nx, ny, 0), dist+1));
                                used[nx][ny] = 1;
                                if (s[nx][ny] == '.') {
                                    g.add_edge(nid(i, j, 0), nid(nx, ny, 1), 1, 1000-(nx+ny));
                                }
                            }
                        }
                    };
                    update(x+1, y);
                    update(x, y+1);
                }
            }
        }
    }
    auto d = g.flow(start, target, cnt);
    ans += (1000*cnt - d.second);
    cout << ans << endl;
    return 0; 
}


int main(){/*{{{*/
    solve();
    check_input();
    return 0;
}/*}}}*/



Measured memory_bytes: 8576