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#pragma GCC optimize("O3")
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// using namespace __gnu_pbds;
// gp_hash_table<int, int> mapka;

using namespace std;
#define PB push_back
#define MP make_pair
#define LL long long
#define int LL
#define FOR(i,a,b) for(int i = (a); i <= (b); i++)
#define RE(i,n) FOR(i,1,n)
#define REP(i,n) FOR(i,0,(int)(n)-1)
#define R(i,n) REP(i,n)
#define VI vector<int>
#define PII pair<int,int>
#define LD long double
#define FI first
#define SE second
#define st FI
#define nd SE
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())

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 TH> void _dbg(const char *sdbg, TH h){ cerr<<sdbg<<'='<<h<<endl; }
template<class TH, class... TA> void _dbg(const char *sdbg, TH h, TA... a) {
  while(*sdbg!=',')cerr<<*sdbg++;
  cerr<<'='<<h<<','; _dbg(sdbg+1, a...);
}

template<class T> ostream &operator<<(ostream& os, vector<T> V) {
  os << "["; for (auto vv : V) os << vv << ","; return os << "]";
}
template<class L, class R> ostream &operator<<(ostream &os, pair<L,R> P) {
  return os << "(" << P.st << "," << P.nd << ")";
}

#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (__VA_ARGS__)
#define cerr if(0)cout
#endif

int n,m;
vector<int> dp[8][8][9][1 << 8];
int lim;
vector<int> licz(int x,int y,int pion,int mb){
  if(y == m){
    x++;
    y = 0;
  }
  if(x == n){
    return {pion == 0};
  }
  vector<int> &res = dp[x][y][pion][mb];
  if(!res.empty())return res;
  res.PB(0);
  
  if(pion){
    int pom = 0;
    if(x != 0)
      pom += (((mb >> (m - 1)) & 1) == 0);
    if(y != 0)
      pom += ((mb & 1) == 0);
    
    vector<int> ak = licz(x,y+1,pion-1,((mb << 1) & lim) + 1);
    if(SZ(res) < SZ(ak) + pom)
      res.resize(SZ(ak) + pom);
    R(i,SZ(ak)){
      res[i + pom] += ak[i];
    }
  }
  int pom = 0;
  if(x != 0)
    pom += ((mb >> (m - 1)) & 1);
  if(y != 0){
    pom += (mb & 1);
  }
  vector<int> ak = licz(x,y+1,pion,((mb << 1) & lim));
  if(SZ(res) < SZ(ak) + pom)
    res.resize(SZ(ak) + pom);
  R(i,SZ(ak)){
    res[i + pom] += ak[i];
  }
  return res;
  
}
int32_t main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout << fixed << setprecision(14);
  cerr << fixed << setprecision(6);
  cin >> n >> m;
  int parz = 0;
  vector<string> t(n);
  int k = 0;
  R(_,2){
    R(i,n){
      cin >> t[i];
      debug(t[i]);
      R(j,m){
        if(t[i][j] == 'O'){
          parz += i + j;
          k++;
        }
      }
    }
  }
  if(parz & 1){
    cout << "0\n";
    return 0;
  }
  k/=2;
  lim = (1 << m) - 1;
  vector<int> rozklad = licz(0, 0, k, 0);
  debug(rozklad);
  LD sum = 0;
  assert(rozklad[0] == 0);
  R(i,SZ(rozklad)){
    sum += rozklad[i] * i;
  }
  int ja = 0;
  R(i,n)R(j,m-1)if(t[i][j] != t[i][j+1])ja++;
  R(i,n-1)R(j,m)if(t[i][j] != t[i+1][j])ja++;
  debug(ja);
  cout << 2 * ja / sum << "\n";
}