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#include <bits/stdc++.h>

using namespace std;

#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return {i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (c it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(x...) " [" #x ": " << (x) << "] "

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
template <typename A, typename B>
using unordered_map2 = __gnu_pbds::gp_hash_table<A, B>;
using namespace __gnu_pbds;
template <typename T> using ordered_set =
  __gnu_pbds::tree<T, __gnu_pbds::null_type, less<T>, __gnu_pbds::rb_tree_tag,
                   __gnu_pbds::tree_order_statistics_node_update>;
// ordered_set<int> s; s.insert(1); s.insert(2);
// s.order_of_key(1);    // Out: 0.
// *s.find_by_order(1);  // Out: 2.

using ld = long double;
using ll = long long;

constexpr int mod = 1000 * 1000 * 1000 + 7;
constexpr int odw2 = (mod + 1) / 2;

void OdejmijOd(int& a, int b) { a -= b; if (a < 0) a += mod; }
int Odejmij(int a, int b) { OdejmijOd(a, b); return a; }
void DodajDo(int& a, int b) { a += b; if (a >= mod) a -= mod; }
int Dodaj(int a, int b) { DodajDo(a, b); return a; }
int Mnoz(int a, int b) { return (ll) a * b % mod; }
void MnozDo(int& a, int b) { a = Mnoz(a, b); }
int Pot(int a, ll b) { int res = 1; while (b) { if (b % 2 == 1) MnozDo(res, a); a = Mnoz(a, a); b /= 2; } return res; }
int Odw(int a) { return Pot(a, mod - 2); }
void PodzielDo(int& a, int b) { MnozDo(a, Odw(b)); }
int Podziel(int a, int b) { return Mnoz(a, Odw(b)); }
int Moduluj(ll x) { x %= mod; if (x < 0) x += mod; return x; }

template <typename T> T Maxi(T& a, T b) { return a = max(a, b); }
template <typename T> T Mini(T& a, T b) { return a = min(a, b); }

ll C(int n, int k) {
  if (!(0 <= k and k <= n)) {
    return 0;
  }
  ll result = 1;
  for (int i = 0; i < k; i++) {
    result *= (n - i);
    result /= (i + 1);
  }
  return result;
}

int n, m, p;
char tab[8][8];

pair<int, int> Wczytaj() {
  p = 0;
  int parz = 0;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      cin >> tab[i][j];
      if (tab[i][j] == '.') {
        // Nic.
      } else if (tab[i][j] == 'O') {
        p++;
        parz = (parz + i + j) % 2;
      } else {
        assert(false);
      }
    }
  }
  int stopien = 0;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (tab[i][j] == 'O') {
        constexpr int di[4] = {-1, 0, 1, 0};
        constexpr int dj[4] = {0, -1, 0, 1};
        for (int h = 0; h < 4; h++) {
          const int ii = i + di[h];
          const int jj = j + dj[h];
          if (0 <= ii and ii < n and 0 <= jj and jj < m) {
            if (tab[ii][jj] == '.') {
              stopien++;
            }
          }
        }
      }
    }
  }
  return {parz, stopien};
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);

  cin >> n >> m;

  auto [sparz, sstop] = Wczytaj();
  auto [kparz, kstop] = Wczytaj();

  const ll kraw = (n * ll(m - 1) + ll(n - 1) * m) * C(n * m - 2, p - 1);

  if (sparz != kparz) {
    cout << 0 << endl;
    return 0;
  }

  cout << fixed << setprecision(17) << (long double) kstop / kraw << endl;
  return 0;
}