#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double dbl;
typedef pair<int,dbl> pid;

const int N=703,M=2e6+3;
const dbl P=acos(0);
int n,m;
string a[N];
int id(int i,int j){
	return i*(m<<1|1)+j;
}
vector<pid> e[M];
int d[M];
void adde(int x,int y,dbl z){
	e[x].emplace_back(y,z);
	++d[y];
}
dbl dis[M];
int main(){
	ios::sync_with_stdio(0);cin.tie(0);
	cin>>n>>m;
	for(int i=0;i<n;++i)cin>>a[i];
	for(int i=0;i<n;++i)
		for(int j=0;j<m;++j){
			adde(id(i<<1,j<<1),id(i<<1|1,j<<1),1);
			adde(id(i<<1,j<<1),id(i<<1,j<<1|1),1);
			adde(id(i<<1|1,j<<1),id(i+1<<1,j<<1),1);
			adde(id(i<<1,j<<1|1),id(i<<1,j+1<<1),1);
			adde(id(i+1<<1,j<<1),id(i+1<<1,j<<1|1),1);
			adde(id(i<<1,j+1<<1),id(i<<1|1,j+1<<1),1);
			adde(id(i<<1|1,j+1<<1),id(i+1<<1,j+1<<1),1);
			adde(id(i+1<<1,j<<1|1),id(i+1<<1,j+1<<1),1);
			if(a[i][j]=='O'){
				adde(id(i<<1,j<<1|1),id(i<<1|1,j+1<<1),P);
				adde(id(i<<1|1,j<<1),id(i+1<<1,j<<1|1),P);
			}
		}
	int vs=(2*n+1)*(2*m+1);
	queue<int> q;
	for(int i=0;i<vs;++i){
		if(!d[i])q.push(i);
		dis[i]=1e9;
	}
	dis[0]=0;
	while(!q.empty()){
		int u=q.front();
		q.pop();
		for(auto&[v,w]:e[u]){
			if(!--d[v])q.push(v);
			dis[v]=min(dis[v],dis[u]+w);
		}
	}
	cout<<fixed<<setprecision(12)<<5*dis[vs-1]<<'\n';
}