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// Arti1990, II UWr

#include <bits/stdc++.h>

#define forr(i, n)                  for(int i=0; i<n; i++)
#define FOREACH(iter, coll)         for(auto iter = coll.begin(); iter != coll.end(); ++iter)
#define FOREACHR(iter, coll)        for(auto iter = coll.rbegin(); iter != coll.rend(); ++iter)
#define lbound(P,K,FUN)             ({auto SSS=P, PPP = P-1, KKK=(K)+1; while(PPP+1!=KKK) {SSS = (PPP+(KKK-PPP)/2); if(FUN(SSS)) KKK = SSS; else PPP = SSS;} PPP;})
#define testy()                     int _tests; cin>>_tests; FOR(_test, 1, _tests)
#define CLEAR(tab)                  memset(tab, 0, sizeof(tab))
#define CONTAIN(el, coll)           (coll.find(el) != coll.end())
#define FOR(i, a, b)                for(int i=a; i<=b; i++)
#define FORD(i, a, b)               for(int i=a; i>=b; i--)
#define MP                          make_pair
#define PB                          push_back
#define ff                          first
#define ss                          second
#define deb(X)                      X;

#define M 1000000007
#define INF 1000000007LL

using namespace std;

int n, m, k;
int binomial[107][107];
vector <string> pocz, kon;
int dd[4][2] = {{-1, 0}, {1, 0}, {0, 1}, {0, -1}};
map <vector<string>, long double> mapa;
long long dp_ile[300][10][10][2], dp_r[300][10][10][2];

void wyswietl(vector <string> pl)
{
    cout << "plansza:\n";
    for(auto s : pl)
        cout << s << '\n';
}

vector <vector <string>> przesuwaj(vector <string> p)
{
    vector <vector<string>> res;
    forr(i, n)
        forr(j, m)
            if(p[i][j] == 'O')
                forr(k, 4)
                {
                    int ni = i + dd[k][0];
                    int nj = j + dd[k][1];
                    if(ni >= 0 && ni < n && nj >= 0 && nj < m && p[ni][nj] == '.')
                    {
                        swap(p[i][j], p[ni][nj]);
                        res.PB(p);
                        swap(p[i][j], p[ni][nj]);
                    }
                }
    return res;
}

int parz(vector <string> str)
{
    int res = 0;
    forr(i, n)
        forr(j, m)
            if(str[i][j] == 'O')
                res += i + j;
    return res%2;
}

int binom(int n, int k)
{
    if(n < 0 || k < 0 || k > n)
        return 0;
    return binomial[n][k];
}

string b(int maska)
{
    string res = "";
    forr(i, m)
        res += ((maska & (1<<i)) > 0)+'0';
    return res;
}

int solve()
{
    cout << fixed;
    cout.precision(17);

    FOR(i, 0, 70)
    {
        binomial[i][0] = 1;
        FOR(j, 1, i)
            binomial[i][j] = binomial[i-1][j-1] + binomial[i-1][j];
    }
    string str;
    cin >> n >> m;
    forr(i, n)
    {
        cin >> str;
        for(auto c : str)
            k += (c == 'O');
        pocz.PB(str);
    }
    forr(i, n)
    {
        cin >> str;
        kon.PB(str);
    }

    int p1 = parz(pocz);
    int p2 = parz(kon);

    forr(maska, (1<<m))
    {
        int pionk = __builtin_popcount(maska);
        int parzyst = __builtin_popcount(maska & (0xAAAAAAAA>>1))&1;
        int lewo = __builtin_popcount(((1<<m)-1) & (maska>>1) & (~maska));
        int prawo = __builtin_popcount(((1<<m)-1) & (maska<<1) & (~maska));
        dp_ile[maska][pionk][1][parzyst] = 1;
        dp_r[maska][pionk][1][parzyst] = lewo + prawo;
        //cout << b(maska) << ", parz: " << parzyst << ", pionk: " << pionk << ", lewo: " << lewo << ", prawo: " << prawo << '\n';
    }

    FOR(poziom, 2, n)
        forr(maska, (1<<m))
            FOR(pionkow, 0, k)
                FOR(parzystosc, 0, 1)
                {
                    forr(pr_maska, (1<<m))
                    {
                        int pionk = __builtin_popcount(maska);
                        int parzyst = __builtin_popcount(maska & (0xAAAAAAAA>>poziom))&1;
                        int lewo = __builtin_popcount(((1<<m)-1) & (maska<<1) & (~maska));
                        int prawo = __builtin_popcount(((1<<m)-1) & (maska>>1) & (~maska));
                        int gora = __builtin_popcount(((1<<m)-1) & (pr_maska) & (~maska));
                        int dol = __builtin_popcount(((1<<m)-1) & (maska) & (~pr_maska));
                        //cout << b(maska) << ", prev: " << b(pr_maska) << ", parz: " << parzyst << ", pionk: " << pionk;
                        //cout << ", lewo: " << lewo << ", prawo: " << prawo << ", gora: " << gora << ", dol: " << dol << '\n';

                        if(pionkow >= pionk)
                        {
                            dp_ile[maska][pionkow][poziom][parzystosc] += dp_ile[pr_maska][pionkow-pionk][poziom-1][parzyst^parzystosc];
                            dp_r[maska][pionkow][poziom][parzystosc] += (lewo + prawo + gora + dol)*dp_ile[pr_maska][pionkow-pionk][poziom-1][parzyst^parzystosc]
                                                                + dp_r[pr_maska][pionkow-pionk][poziom-1][parzyst^parzystosc];
                        }
                    }
                    //cout << "ruchy[" << b(maska) << "][" << pionkow << "][" << poziom << "][" << parzystosc << "] = " << dp_r[maska][pionkow][poziom][parzystosc] << '\n';
                }


    long long ruchow = 0;
    forr(maska, (1<<m))
        ruchow += dp_r[maska][k][n][p2];
    //cout << ruchow << '\n';

    //return 0;
/*
    vector <int> pp({n*m/2, (n*m+1)/2});
    int ile = 0;
    FOR(x, 0, k)
        if(x%2 == p2)
        {
            ile += binom(pp[x%2], x)*binom(pp[1-x%2], k-x);
        }
    cout << "dobrych ustawien: " << ile << '\n';

    mapa[kon] = 1;

    FOR(i, 1, 100)
    {
        auto prev = mapa;
        mapa.clear();

        int ile = 0;
        for(auto el : prev)
        {
            auto nowe = przesuwaj(el.ff);
            ile += nowe.size();
            for(auto pl : nowe)
                mapa[pl] += el.ss/nowe.size();
        }

        cout << "po iteracji " << i << " mamy:" << '\n';
        for(auto el : prev)
        {
            wyswietl(el.ff);
            cout << "ppb: " << el.ss << '\n';
        }
        cout << ile << '\n';
    }

    /*auto prz = przesuwaj(kon);
    for(auto pl : prz)
        wyswietl(pl);
*/
    if(p1 != p2)
    {
        cout << 0 << '\n';
        return 0;
    }

    long double rr = przesuwaj(kon).size();
    rr /= ruchow;
    cout << rr << '\n';

    return 0;
}

int main()
{
    std::ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    solve();

    return 0;
}