//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("unroll-loops")
  
#include <iostream>
#include <stdlib.h>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <assert.h>
#include <memory.h>
#include <time.h>
#include <bitset>

#include "atcoder/convolution.hpp"
#include "atcoder/dsu.hpp"
#include "atcoder/fenwicktree.hpp"
#include "atcoder/lazysegtree.hpp"
#include "atcoder/math.hpp"
#include "atcoder/maxflow.hpp"
#include "atcoder/mincostflow.hpp"
#include "atcoder/modint.hpp"
#include "atcoder/scc.hpp"
#include "atcoder/segtree.hpp"
#include "atcoder/string.hpp"
#include "atcoder/twosat.hpp"

#define uint unsigned int
#define ll long long
#define ull unsigned long long
#define ld long double
#define rep(i, l, r) for (int i = (l); i < (r); i++)
#define repb(i, r, l) for (int i = (r); i > (l); i--)
#define sz(a) (int)a.size()
#define fi first
#define se second
#define mp(a, b) make_pair(a, b)
#define rank qwertyuio
#define next dfghjk
#define prev fhsgfhjf
#define plus fsghsf
#define minus ytryr
  
using namespace std;
using namespace atcoder;
  
inline bool setmin(int &x, int y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(int &x, int y) { return (y > x) ? x = y, 1 : 0; }
inline bool setmin(ll &x, ll y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(ll &x, ll y) { return (y > x) ? x = y, 1 : 0; }
  
const int N = 50;
const int inf = (int)1e9 + 1;
const ll big = (ll)1e18 + 1;
const int P = 239;
const int P1 = 31;
const int P2 = 57;
const int MOD = (int)1e9 + 7;
const int MOD1 = (int)1e9 + 9;
const int MOD2 = 998244353;
const ld eps = 1e-9;
const double pi = atan2(0, -1);
const int ABC = 26;

vector<vector<int> > g;
vector<bool> used;
vector<int> mt;
 
bool dfs(int u)
{
    if (used[u])
        return false;
    used[u] = true;
    for (int v : g[u])
        if (mt[v] == -1 || dfs(mt[v]))
        {
            mt[v] = u;
            return true;
        }
    return false;
}

string a[N];

bool ok[N][N];

int main()
{
    //freopen("circus.in", "r", stdin);
    //freopen("circus.out", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.precision(20);
    cout << fixed;
    //ll TL = 10.95 * CLOCKS_PER_SEC;
    //clock_t time = clock();
    int n, m;
    cin >> n >> m;
    rep(i, 0, n) {
        cin >> a[i];
    }
    int c = 0;
    g.resize(n * m);
    used.resize(n * m);
    rep(x, 0, n) {
        rep(y, 0, m) {
            if (a[x][y] == 'o') {
                mt.push_back(-1);
                rep(i, 0, n) {
                    fill(ok[i], ok[i] + m, false);
                }
                ok[x][y] = true;
                rep(i, 0, n) {
                    rep(j, 0, m) {
                        if (!ok[i][j]) {
                            continue;
                        }
                        g[i * m + j].push_back(c);
                        if (j + 1 < m && a[i][j + 1] != '#') {
                            ok[i][j + 1] = true;
                        }
                        if (i + 1 < n && a[i + 1][j] != '#') {
                            ok[i + 1][j] = true;
                        }
                    }
                }
                c++;
            }
        }
    }
    int ccc = 0;
    repb(s, n - 1 + m - 1, -1) {
        rep(i, max(0, s - (m - 1)), min(n - 1, s) + 1) {
            int j = s - i;
            assert(j >= 0 && j < m);
            ccc++;
            if (a[i][j] == '#') {
                continue;
            }
            fill(used.begin(), used.end(), false);
            dfs(i * m + j);
        }
    }
    assert(ccc == n * m);
    int ans = 0;
    rep(i, 0, c) {
        assert(mt[i] != -1);
        ans += mt[i] / m + mt[i] % m;
    }
    rep(i, 0, n) {
        rep(j, 0, m) {
            if (a[i][j] == 'o') {
                ans -= i;
                ans -= j;
            }
        }
    }
    cout << ans << "\n";
    return 0;
}



Measured memory_bytes: 4084