#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#include <time.h>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <cstring>

using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <iostream>

using namespace __gnu_pbds;
using namespace std;
template <class T>
using Tree =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// to erase in multiset-> less_equal<T> and 
// s.erase(s.find_by_order(s.order_of_key(x)))
// lower_bound(x)=>(cannot use the stl lower_bound function)
// ll idx = s.order_of_key(x)
// if(idx == s.size()) -> no lower_bound
// else lb = *s.find_by_order(idx) // as 0-indexing
// idx-1 will give highest value which is strictly less than x
// for upper_bound->do the same with (x+1)

typedef long long ll;
typedef long double ld;
typedef pair<int,int> p32;
typedef pair<ll,ll> p64;
typedef tuple<ll, ll, ll> t64;
typedef vector<t64> vt64;
typedef vector<vt64> vvt64;
typedef pair<double,double> pdd;
typedef vector<ll> v64;
typedef vector<int> v32;
typedef vector<vector<int> > vv32;
typedef vector<vector<ll> > vv64;
typedef vector<vector<p64> > vvp64;
typedef vector<p64> vp64;
typedef vector<p32> vp32;
typedef vector<vector<p32> > vvp32;
typedef vector<bool> vb;
ll mod =  1e9+7, MOD = 998244353;
double eps = 1e-12;
// #define forn(i,e) for(ll i = 0; i < e; i++)
#define FOR(s, e, i) for(int i = s; i <= e; i++)
// #define rforn(i,s) for(ll i = s; i >= 0; i--)
#define ROF(s ,e, i) for(int i = s; i >= e; i--)
#define coutAll(A) for(auto asdafas : A) cout <<  asdafas << " "; cout << "\n";
#define foutAll(A) for(auto asdafas : A) fout <<  asdafas << " "; cout << "\n";
#define cinAll(A) for(auto &asdafas : A) cin >>  asdafas;
#define finAll(A) for(auto &asdafas : A) fin >>  asdafas;
#define minpq priority_queue<ll, v64, greater<ll>>
#define maxpq priority_queue<ll> 
#define ln "\n"
#define dbg(x) cout<<#x<<" = "<<x<<ln
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define fi first
#define se second
ll inf = LLONG_MAX;
#define fast_cin() ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef pair<ll, ll> pll;
typedef pair<ll, ll> pii;
//#define MAXN 1000000

void solve(int it)
{
    int h, w;
    cin >> h >> w;
    int H = 2*h+1;
    int W = 2*w+1;
    map<p32, ll>cmp;
    map<ll, p32>revcmp;
    int sz = 0;
    FOR(0, H - 1, i){
        FOR(0, W - 1, j){
            cmp[{i, j}] = sz;
            revcmp[sz] = {i, j};
            ++sz;
        }
    }
    vector<string>A(h); cinAll(A);
    int di[] = {1, -1, 0, 0};
    int dj[] = {0, 0, 1, -1};
    auto valid = [&](int i, int j)->bool{
        return 0 <= i && i < H && 0 <= j && j < W;
    };
    vector<vector<pair<int, double>>>adj(sz);
    FOR(0, H - 1, i){
        FOR(0, W - 1, j){
            if(i % 2 && j % 2) continue;
            if(i % 2 == 0 && j % 2 == 0)
                FOR(0, 3, d){
                    int ni = i + di[d];
                    int nj = j + dj[d];
                    if(valid(ni, nj)){
                        adj[cmp[{i, j}]].pb({cmp[{ni, nj}], 5});
                    }
                }
            else if(i % 2 == 1 && j % 2 == 0)
                FOR(0, 3, d){
                    if(di[d] == 0) continue;
                    int ni = i + di[d];
                    int nj = j + dj[d];
                    if(valid(ni, nj)){
                        adj[cmp[{i, j}]].pb({cmp[{ni, nj}], 5});
                    }
                }
            else
                FOR(0, 3, d){
                    if(dj[d] == 0) continue;
                    int ni = i + di[d];
                    int nj = j + dj[d];
                    if(valid(ni, nj)){
                        adj[cmp[{i, j}]].pb({cmp[{ni, nj}], 5});
                    }
                }
        }
    }
    auto add_edge = [&](int u, int v, double wt)->void{
        adj[u].pb({v, wt});
        adj[v].pb({u, wt});
    };
    double arc = acos(-1)*5.0/2;
    FOR(0, h - 1, i){
        FOR(0, w - 1, j){
            if(A[i][j] == 'O'){
                int I = 2*i, J = 2*j+1;
                int _I = 2*i+2, _J = 2*j+1;
                int I_ = 2*i+1, J_ = 2*j;
                int I__ = 2*i+1, J__ = 2*j+2;
                add_edge(cmp[{I, J}], cmp[{I_, J_}], arc);
                add_edge(cmp[{I, J}], cmp[{I__, J__}], arc);
                add_edge(cmp[{_I, _J}], cmp[{I_, J_}], arc);
                add_edge(cmp[{_I, _J}], cmp[{I__, J__}], arc);
            }
        }
    }   
    // FOR(0, sz -1 , i){
    //     cout << revcmp[i].fi << " " << revcmp[i].se << "->\n";
    //     for(auto x : adj[i]){
    //         cout << "(" << revcmp[x.fi].fi << " " << revcmp[x.fi].se
    //              << " " << x.se << "), ";
    //     }
    //     cout << "\n";
    // }
    priority_queue<pair<int, double>, vector<pair<int, double>>,
    greater<pair<int, double>>>q;
    q.push({0, cmp[{0, 0}]});
    vector<double>dist(sz, 1e18);
    dist[cmp[{0, 0}]] = 0;
    while(!q.empty()){
        auto u = q.top();
        q.pop();
        if(u.fi > dist[u.se]) continue;
        for(auto v : adj[u.se]){
            if(dist[v.fi] > dist[u.se] + v.se){
                dist[v.fi] = dist[u.se] + v.se;
                q.push({dist[v.fi], v.fi});
            }
        }   
    }
    // coutAll(dist);
    cout << fixed << setprecision(20) << dist.back();




}


int main()
{
    fast_cin();    
    ll t = 1;
    // cin >> t;
    for(int it=1; it<=t; it++)
    {
        //cout << "Case " << it << ": ";
        solve(it);
    }
    return 0;
}