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#include <bits/stdc++.h>
#define MP make_pair
#define PB push_back
#define int long long
#define st first
#define nd second
#define rd third
#define FOR(i, a, b) for(int i =(a); i <=(b); ++i)
#define RE(i, n) FOR(i, 1, n)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define REP(i, n) for(int i = 0;i <(n); ++i)
#define VAR(v, i) __typeof(i) v=(i)
#define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define __builtin_ctz __builtin_ctzll
#define __builtin_clz __builtin_clzll
#define __builtin_popcount __builtin_popcountll
using namespace std;
template<typename TH> void _dbg(const char* sdbg, TH h) { cerr<<sdbg<<"="<<h<<"\n"; }
template<typename TH, typename... TA> void _dbg(const char* sdbg, TH h, TA... t) {
  while(*sdbg != ',') { cerr<<*sdbg++; } cerr<<"="<<h<<","; _dbg(sdbg+1, t...);
}
#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x) {{cerr <<#x <<" = "; FORE(itt, (x)) cerr <<*itt <<", "; cerr <<"\n"; }}
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define cerr if(0)cout
#endif
#define next ____next
#define prev ____prev
#define left ____left
#define hash ____hash
typedef long long ll;
typedef long double LD;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<pair<int, int> > VPII;
typedef vector<pair<ll, ll> > VPLL;

template<class C> void mini(C&a4, C b4){a4=min(a4, b4); }
template<class C> void maxi(C&a4, C b4){a4=max(a4, b4); }
template<class T1, class T2>
ostream& operator<< (ostream &out, pair<T1, T2> pair) { return out << "(" << pair.first << ", " << pair.second << ")";}
template<class A, class B, class C> struct Triple { A first; B second; C third;
  bool operator<(const Triple& t) const { if (st != t.st) return st < t.st; if (nd != t.nd) return nd < t.nd; return rd < t.rd; } };
template<class T> void ResizeVec(T&, vector<int>) {}
template<class T> void ResizeVec(vector<T>& vec, vector<int> sz) {
  vec.resize(sz[0]); sz.erase(sz.begin()); if (sz.empty()) { return; }
  for (T& v : vec) { ResizeVec(v, sz); }
}
typedef Triple<int, int, int> TIII;
template<class A, class B, class C>
ostream& operator<< (ostream &out, Triple<A, B, C> t) { return out << "(" << t.st << ", " << t.nd << ", " << t.rd << ")"; }
template<class T> ostream& operator<<(ostream& out, vector<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }
template<class T> ostream& operator<<(ostream& out, set<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }
template<class L, class R> ostream& operator<<(ostream& out, map<L, R> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }

const int N = 100;
int newt[N][N];

int32_t main() {

  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(15);
  cerr << fixed << setprecision(15);
  cin.tie(0);
  //double beg_clock = 1.0 * clock() / CLOCKS_PER_SEC;
  

  int n, m;
  cin>>n>>m;
  int k = 0;
  VI par(2);
  int en_deg = 0;
  REP (tr, 2) {
    vector<vector<char>> board(n + 2, vector<char>(m + 2));
    RE (i, n) {
      RE (j, m) {
        char c;
        cin>>c;
        board[i][j] = c;
        if (c == 'O') {
          debug(i, j);
          par[tr] ^= (i + j) % 2;
          k += tr;
        }
      }
    }
    if (tr == 1) {
      RE (i1, n) {
        RE (j1, m) {
          RE (i2, n) {
            RE (j2, m) {
              if (abs(i1 - i2) + abs(j1 - j2) != 1) { continue; }
              if (board[i1][j1] == 'O' && board[i2][j2] == '.') { en_deg++; }
            }
          }
        }
      }
    }
  }
  debug(par[0], par[1]);
  if (par[0] != par[1]) {
    cout<<"0\n";
    return 0;
  }
  
  REP (i, N) {
    newt[i][0] = newt[i][i] = 1;
    RE (j, i - 1) {
      newt[i][j] = newt[i - 1][j] + newt[i - 1][j - 1];
    }
  }
  debug(newt[64][8]);
  
  int pairs = 2 * (n * (m - 1) + m * (n - 1));
  int mul = newt[n * m - 1][k - 1];
  if (k >= 2) {
    mul -= newt[n * m - 2][k - 2];
  }
  int sum_deg = pairs * mul;
  debug(en_deg, sum_deg);
  cout<<en_deg * (LD)2 / sum_deg<<endl;
    
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  return 0;
}