#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define rng(i,c,n) for(int i=c;i<n;i++)
#define fi first
#define se second
#define pb push_back
#define sz(a) (int) a.size()
#define all(a) a.begin(),a.end()
#define vec(...) vector<__VA_ARGS__>
#define _3Wcdivh ios::sync_with_stdio(0),cin.tie(0)
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pii;
void print(){cout<<'\n';}
template<class h,class...t>
void print(const h&v,const t&...u){cout<<v<<' ',print(u...);}

const int inf=1e9;

int n,m;

void slv(){
	vec(string) a(n);
	rep(i,n){
		cin>>a[i];
	}

	int mi_i=n,ma_i=-1;
	rep(i,n){
		rep(j,m){
			if(a[i][j]=='O'){
				mi_i=min(mi_i,i);
				ma_i=max(ma_i,i);
			}
		}
	}
	int mi_j=m,ma_j=0;
	rng(i,mi_i,ma_i+1){
		rep(j,m){
			if(a[i][j]=='O'){
				ma_j=max(ma_j,j);
				mi_j=min(mi_j,j);
			}
		}
	}

	vi qsr(m,-1);
	{
		int now=0;
		rng(i,mi_i,ma_i+1){
			rep(j,m){
				if(a[i][j]=='O'){
					now=max(now,j);
				}
			}
			qsr[i]=now;
		}
		now=0;
		per(i,ma_i+1){
			if(i<mi_i) break;
			rep(j,m){
				if(a[i][j]=='O'){
					now=max(now,j);
				}
			}
			if(now==ma_j) break;
			qsr[i]=now;
		}
	}
	vi qsl(m,m);
	{
		int now=m;
		rng(i,mi_i,ma_i+1){
			rep(j,m){
				if(a[i][j]=='O'){
					now=min(now,j);
				}
			}
			qsl[i]=now;
		}
		now=m;
		per(i,ma_i+1){
			if(i<mi_i) break;
			rep(j,m){
				if(a[i][j]=='O'){
					now=min(now,j);
				}
			}
			if(now==mi_j) break;
			qsl[i]=now;
		}
	}
	
	int ans=0;
	ans+=(ma_i-mi_i+1)*2+(ma_j-mi_j+1)*2;

	vec(vi) usd(n,vi(m));
	rng(i,mi_i,ma_i+1){
		// print(qsl[i],qsr[i]);
		rng(j,qsl[i],qsr[i]+1){
			usd[i][j]=1;
		}
	}

	pii p{-1,-1};
	rep(i,n){
		rep(j,m){
			if(a[i][j]=='X'){
				p={i,j};
			}
		}
	}
	assert(p!=pii(-1,-1));
	
	// rep(i,n){
	// 	rep(j,m){
	// 		cout<<usd[i][j];
	// 	}
	// 	print();
	// }
	// print();

	if(!usd[p.fi][p.se]){
		cout<<ans<<"\n";
	}else if(mi_i==ma_i or mi_j==ma_j){
		if(n==1 or m==1){
			cout<<"-1\n";
		}else{
			cout<<ans+4<<"\n";
		}
	}else{
		ans+=2;
		const int di[]={1,-1,0,0};
		const int dj[]={0,0,1,-1};
		auto ok=[&](int i,int j)->int{
			return min(i,j)>=0 and i<n and j<m;
		};
		int val=inf;
		vec(vi) dist(n,vi(m,-1));
		dist[p.fi][p.se]=0;
		queue<pii> que;
		que.push({p.fi,p.se});
		while(sz(que)){
			auto [i,j]=que.front();
			que.pop();
			if(!usd[i][j]){
				val=min(val,dist[i][j]);
			}
			rep(dir,4){
				int ni=i+di[dir],nj=j+dj[dir];
				if(!ok(ni,nj)){
					val=min(val,dist[i][j]);
				}else if(a[ni][nj]!='O'){
					if(dist[ni][nj]==-1){
						if(!usd[ni][nj]){
							val=min(val,dist[i][j]);
						}
						dist[ni][nj]=dist[i][j]+1;
						que.push({ni,nj});
					}
				}
			}
		}
		if(val==inf){
			cout<<"-1\n";
			return;
		}
		val*=2;
		ans+=val;
		cout<<ans<<"\n";
	}
}

signed main(){
_3Wcdivh;
	while(cin>>n>>m){
		slv();
	}
}