#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
#include<array>
#include<chrono>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
//ll mod = 1;
constexpr ll mod = 998244353;
//constexpr ll mod = 1000000007;
const int mod17 = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int>P;

#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;

using ld = double;
typedef pair<ld, ld> LDP;
const ld eps = 1e-10;
const ld pi = acosl(-1.0);

template<typename T>
void chmin(T& a, T b) {
	a = min(a, b);
}
template<typename T>
void chmax(T& a, T b) {
	a = max(a, b);
}
template<typename T>
vector<T> vmerge(vector<T>& a, vector<T>& b) {
	vector<T> res;
	int ida = 0, idb = 0;
	while (ida < a.size() || idb < b.size()) {
		if (idb == b.size()) {
			res.push_back(a[ida]); ida++;
		}
		else if (ida == a.size()) {
			res.push_back(b[idb]); idb++;
		}
		else {
			if (a[ida] < b[idb]) {
				res.push_back(a[ida]); ida++;
			}
			else {
				res.push_back(b[idb]); idb++;
			}
		}
	}
	return res;
}
template<typename T>
void cinarray(vector<T>& v) {
	rep(i, v.size())cin >> v[i];
}
template<typename T>
void coutarray(vector<T>& v) {
	rep(i, v.size()) {
		if (i > 0)cout << " "; cout << v[i];
	}
	cout << "\n";
}
ll mod_pow(ll x, ll n, ll m = mod) {
	if (n < 0) {
		ll res = mod_pow(x, -n, m);
		return mod_pow(res, m - 2, m);
	}
	if (abs(x) >= m)x %= m;
	if (x < 0)x += m;
	//if (x == 0)return 0;
	ll res = 1;
	while (n) {
		if (n & 1)res = res * x % m;
		x = x * x % m; n >>= 1;
	}
	return res;
}
//mod should be <2^31
struct modint {
	int n;
	modint() :n(0) { ; }
	modint(ll m) {
		if (m < 0 || mod <= m) {
			m %= mod; if (m < 0)m += mod;
		}
		n = m;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
bool operator<(modint a, modint b) { return a.n < b.n; }
modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= (int)mod; return a; }
modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += (int)mod; return a; }
modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, ll n) {
	if (n == 0)return modint(1);
	modint res = (a * a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
modint operator/=(modint& a, modint b) { a = a / b; return a; }
const int max_n = 1 << 20;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
modint combP(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[a - b];
}

ll gcd(ll a, ll b) {
	a = abs(a); b = abs(b);
	if (a < b)swap(a, b);
	while (b) {
		ll r = a % b; a = b; b = r;
	}
	return a;
}
template<typename T>
void addv(vector<T>& v, int loc, T val) {
	if (loc >= v.size())v.resize(loc + 1, 0);
	v[loc] += val;
}
/*const int mn = 2000005;
bool isp[mn];
vector<int> ps;
void init() {
	fill(isp + 2, isp + mn, true);
	for (int i = 2; i < mn; i++) {
		if (!isp[i])continue;
		ps.push_back(i);
		for (int j = 2 * i; j < mn; j += i) {
			isp[j] = false;
		}
	}
}*/

//[,val)
template<typename T>
auto prev_itr(set<T>& st, T val) {
	auto res = st.lower_bound(val);
	if (res == st.begin())return st.end();
	res--; return res;
}

//[val,)
template<typename T>
auto next_itr(set<T>& st, T val) {
	auto res = st.lower_bound(val);
	return res;
}
using mP = pair<modint, modint>;
mP operator+(mP a, mP b) {
	return { a.first + b.first,a.second + b.second };
}
mP operator+=(mP& a, mP b) {
	a = a + b; return a;
}
mP operator-(mP a, mP b) {
	return { a.first - b.first,a.second - b.second };
}
mP operator-=(mP& a, mP b) {
	a = a - b; return a;
}
LP operator+(LP a, LP b) {
	return { a.first + b.first,a.second + b.second };
}
LP operator+=(LP& a, LP b) {
	a = a + b; return a;
}
LP operator-(LP a, LP b) {
	return { a.first - b.first,a.second - b.second };
}
LP operator-=(LP& a, LP b) {
	a = a - b; return a;
}

mt19937 mt(time(0));

const string drul = "DRUL";
string senw = "SENW";
//DRUL,or SENW
//int dx[4] = { 1,0,-1,0 };
//int dy[4] = { 0,1,0,-1 };

//------------------------------------

int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };

void solve() {
	int h, w; cin >> h >> w;
	vector<string> s(h);
	rep(i, h)cin >> s[i];
	vector<vector<bool>> ok(h, vector<bool>(w));
	rep(i, h)rep(j, w) {
		if (i == 0 || i == h - 1 || j == 0 || j == w - 1) {
			ok[i][j] = false;
		}
		else {
			ok[i][j] = true;
			for (int ni = i - 1; ni <= i + 1; ni++) {
				for (int nj = j - 1; nj <= j + 1; nj++) {
					if (s[ni][nj] == '#')ok[i][j] = false;
				}
			}
		}
	}
	auto isin = [&](int i, int j) {
		return 0 < i && i < h - 1 && 0 < j && j < w - 1 && P{ i,j } != P{ 1,1 } && P{ i,j } != P{ h - 2,w - 2 };
	};
	auto nexs = [&](int i, int j) {
		vector<P> res;
		for (int adi = -2; adi <= 2; adi++) {
			for (int adj = -2; adj <= 2; adj++) {
				if (abs(adi) == 2 && abs(adj) == 2)continue;
				int ni = i + adi;
				int nj = j + adj;
				bool valid = true;
				Rep1(nni, ni - 1, ni + 1)Rep1(nnj, nj - 1, nj + 1) {
					if (!isin(nni, nnj)) {
						valid = false;
					}
				}
				if (valid) {
					Rep1(nni, ni - 1, ni + 1)Rep1(nnj, nj - 1, nj + 1) {
						res.push_back({ nni,nnj });
					}
				}
			}
		}
		return res;
	};
	using speP = pair<int, P>;
	priority_queue<speP, vector<speP>, greater<speP>> q;
	vector<vector<int>> dist(h, vector<int>(w, mod17));
	for (int i = 2; i < h; i++) {
		int j = 0;
		auto tos = nexs(i, j);
		for (P pto : tos) {
			int ni = pto.first, nj = pto.second;
			if (dist[ni][nj] > 1) {
				dist[ni][nj] = 1; q.push({ 1,{ni,nj} });
			}
		}
		rep(d, 4) {
			int ni = i + dx[d];
			int nj = j + dy[d];
			if (isin(ni, nj)&&!ok[ni][nj]) {
				dist[ni][nj] = 0;
				q.push({ 0,{ni,nj} });
			}
		}
	}
	for (int j = 0; j < w - 2; j++) {
		int i = h - 1;
		auto tos = nexs(i, j);
		for (P pto : tos) {
			int ni = pto.first, nj = pto.second;
			if (dist[ni][nj] > 1) {
				dist[ni][nj] = 1; q.push({ 1,{ni,nj} });
			}
		}
		rep(d, 4) {
			int ni = i + dx[d];
			int nj = j + dy[d];
			if (isin(ni, nj)&&!ok[ni][nj]) {
				dist[ni][nj] = 0;
				q.push({ 0,{ni,nj} });
			}
		}
	}
	while (!q.empty()) {
		auto pp = q.top(); q.pop();
		int cd = pp.first;
		int i = pp.second.first;
		int j = pp.second.second;
		if (dist[i][j] < cd)continue;
		rep(d, 4) {
			int ni = i + dx[d];
			int nj = j + dy[d];
			if (isin(ni,nj)&&dist[ni][nj] > cd&&!ok[ni][nj]) {
				dist[ni][nj] = cd; q.push({ dist[ni][nj],{ni,nj} });
			}
		}
		auto tos = nexs(i, j);
		for (auto pto : tos) {
			int ni = pto.first;
			int nj = pto.second;
			if (dist[ni][nj] > cd + 1) {
				dist[ni][nj] = cd + 1; q.push({ dist[ni][nj],{ni,nj} });
			}
		}
	}
	//rep(i, h)coutarray(dist[i]);
	int ans = mod17;
	for (int j = 2; j < w - 1; j++) {
		chmin(ans, dist[1][j]);
	}
	for (int i = 1; i < h - 2; i++) {
		chmin(ans, dist[i][w - 2]);
	}
	cout << ans << "\n";
}




signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed<<setprecision(10);
	//init_f();
	//init();
	//init2();
	//while(true)
	//expr();
	//int t; cin >> t; rep(i, t)
	solve();
	return 0;
}