// Author: Kajetan Ramsza
#include "bits/stdc++.h"

using namespace std;

template<typename F, typename S> ostream& operator<<(ostream& os, const pair<F, S> &p) { return os<<"("<<p.first<<", "<<p.second<<")"; }
template<typename T> ostream &operator<<(ostream & os, const vector<T> &v) { os << "{"; typename vector< T > :: const_iterator it;
    for( it = v.begin(); it != v.end(); it++ ) { if( it != v.begin() ) os << ", "; os << *it; } return os << "}"; }

void dbg_out() { cerr<<'\n'; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr<<' '<<H; dbg_out(T...); }

#ifdef DEBUG
#define dbg(...) cerr<<"(" << #__VA_ARGS__ <<"):", dbg_out(__VA_ARGS__)
#else
#define dbg(...) 
#endif

typedef long long ll;
typedef long double ld;

struct Board {
    int n, m;
    vector<vector<bool>> vec;

    Board() {}
    Board(int n_, int m_) : n(n_), m(m_) {
        vec.assign(n, vector<bool>(m));
    } 

    int read() {
        int res = 0;
        for(int i=0;i<n;i++) {
            for(int j=0;j<m;j++) {
                char c;
                cin>>c;
                vec[i][j] = c == 'O';
                res += vec[i][j];
            }
        }
        return res;
    }

    // void read(const vector<bool> &val) {
    //     assert((int)val.size() == n*m);
    //     for(int i=0;i<n;i++) {
    //         for(int j=0;j<m;j++) {
    //             vec[i][j] = val[n*i + j];
    //         }   
    //     }
    // }

    bool parity() {
        int res = 0;
        for(int i=0;i<n;i++) {
            for(int j=0;j<m;j++) {
                if(vec[i][j])
                    res += i + j;
            }   
        }
        return res % 2;
    }

    bool empty(int i, int j) {
        if(n <= i || i < 0) return false;
        if(m <= j || j < 0) return false;
        return !vec[i][j];
    }

    int infl() {
        int res = 0;
        for(int i=0;i<n;i++) {
            for(int j=0;j<m;j++) {
                if(vec[i][j]) {
                    res += empty(i-1, j);
                    res += empty(i, j-1);
                    res += empty(i+1, j);
                    res += empty(i, j+1);
                }
            }   
        }
        return res;
    }
};

int n, m;
int pawns;

Board board;
Board goal;

bool parity;

ll sum;

const int maxnm = 66;
const int maxp = 9;
ll nchoosek[maxnm][maxp];

void preprocess() {
    nchoosek[0][0] = 1;
    for(int i=1;i<maxnm;i++) {
        for(int j=0;j<=min(maxp-1, i);j++) {
            nchoosek[i][j] = 1;
            for(ll k=i-j+1;k<=i;k++) {
                nchoosek[i][j] *= k;
            }
            for(ll k=2;k<=j;k++)
                nchoosek[i][j] /= k;
            dbg(i, j, nchoosek[i][j]);
        }
    }
}

ll infl(int i, int j) {
    dbg("-------------", i, j);
    ll result = 0;
    int even = (n*m+1) / 2;
    int odd = (n*m) / 2;
    if((i+j) % 2) odd--;
    else even--;
    for(int l=0;l<2;l++) {
        for(int r=0;r<2;r++) {
            for(int u=0;u<2;u++) {
                for(int d=0;d<2;d++) {
                    int pawn = pawns - 1;
                    int e = even;
                    int o = odd;
                    bool p = parity ^ ((i+j) % 2);
                    if(i == 0 && u == 1) continue;
                    if(i == n-1 && d == 1) continue;
                    if(j == 0 && l == 1) continue;
                    if(j == m-1 && r == 1) continue;
                    dbg("NOT SKIPPED");
                    if(i != 0) {
                        if((i+j-1) % 2) o--;
                        else e--;
                    }
                    if(i != n-1) {
                        if((i+j+1) % 2) o--;
                        else e--;
                    }
                    if(j != 0) {
                        if((i+j-1) % 2) o--;
                        else e--;
                    }
                    if(j != m-1) {
                        if((i+j+1) % 2) o--;
                        else e--;                  
                    }
                    if(l == 1) {
                        p ^= ((i+j-1) % 2);
                        pawn--;
                    }
                    if(r == 1) {
                        p ^= ((i+j+1) % 2);
                        pawn--;
                    }
                    if(u == 1) {
                        p ^= ((i+j-1) % 2);
                        pawn--;
                    }
                    if(d == 1) {
                        p ^= ((i+j+1) % 2);
                        pawn--;
                    }
                    dbg(p, l, r, u, d, e, o, pawn);
                    if(pawn < 0) continue;
                    ll res = 0;
                    for(int k=p;k<=min(o,pawn);k+=2) {
                        dbg(o, e, k);
                        dbg(e , pawn - k);
                        dbg(nchoosek[o][k], nchoosek[e][pawn - k]);
                        if(pawn - k > e) continue;
                        res += nchoosek[o][k] * nchoosek[e][pawn - k];
                    }
                    ll num = 0;
                    if(i != 0 && u == 0) num++;
                    if(i != n-1 && d == 0) num++;
                    if(j != 0 && l == 0) num++;
                    if(j != m-1 && r == 0) num++;
                    dbg(res, num);
                    result += res * num;
                }
            }
        }
    }
    dbg(result);
    return result;
}

void solve() {
    preprocess();
    for(int i=0;i<n;i++) {
        for(int j=0;j<m;j++) {
            sum += infl(i, j);
        }
    }
    // sum /= pawns;
}

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

    cin>>n>>m;
    board = Board(n, m);
    pawns = board.read();
    parity = board.parity();
    dbg(parity);
    goal = Board(n, m);
    goal.read();
    if(parity != goal.parity()) {
        cout<<0<<'\n';
        return 0;
    }
    solve();
    ll infl = goal.infl();
    dbg(infl, sum);
    cout<<fixed<<setprecision(15);
    cout<<(ld)infl / (ld)sum<<'\n';
}