#include <bits/stdc++.h>
#include <atcoder/all>
#define SELECTER(_1,_2,_3,SELECT,...) SELECT
#define rep1(i,n) for(int i=0;i<(int)n;++i)
#define rep2(i,a,n) for(int i=(int)a;i<(int)n;++i)
#define rep(...) SELECTER(__VA_ARGS__,rep2,rep1)(__VA_ARGS__)
#define RSELECTER(_1, _2, _3, RSELECT, ...) RSELECT
#define rrep1(i,n) for(int i=(int)n-1;i>=0;--i)
#define rrep2(i,a,n) for(int i=(int)n-1;i>=(int)a;--i)
#define rrep(...) RSELECTER(__VA_ARGS__, rrep2, rrep1)(__VA_ARGS__)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define fi first
#define se second
#define PrintR LogOutput
#ifdef _DEBUG
#define Log(...) LogOutput(__VA_ARGS__)
#else
#define Log(...)
#endif
using namespace std;
using namespace atcoder;
using ll=long long;
using pii=pair<int,int>;
using pll=pair<long long,long long>;
using pdd=pair<long double,long double>;
using veci=vector<int>;
using vecpii=vector<pair<int,int>>;
using vecll=vector<long long>;
using vecpll=vector<pair<long long,long long>>;
using vecpdd=vector<pair<long double,long double>>;
using vecs=vector<string>;
using vecb=vector<bool>;
using vecd=vector<long double>;
using tp=tuple<int,int,int>;
using tpll=tuple<ll,ll,ll>;
using mint=modint998244353;
using mint10=modint1000000007;
template<typename T, typename S>
istream& operator>>(istream& in, pair<T, S>& a){return in >> a.first >> a.second;}
template<typename T, typename S>
ostream& operator<<(ostream& out, const pair<T, S>& a){return out << a.first << ' ' << a.second;}
ostream& operator<<(ostream& out, const mint& a){return out << a.val();}
ostream& operator<<(ostream& out, const mint10& a){return out << a.val();}
ostream& operator<<(ostream& out, const modint& a){return out << a.val();}
template<typename T>
ostream& operator<<(ostream& out, const vector<T>& d){for(int i = 0 ; i < d.size() ; ++i) out << d[i] << (i == d.size() - 1 ? "" : " "); return out;}
template<typename T, typename S>
pair<T, S> operator+(const pair<T, S>& a, const pair<T, S>& b){return {a.fi + b.fi, a.se + b.se};}
template<typename T, typename S>
pair<T, S> operator-(const pair<T, S>& a, const pair<T, S>& b){return {a.fi - b.fi, a.se - b.se};}
template<class T> inline bool chmax(T& a,T b){if(a<b) {a=b;return true;} return false;}
template<class T> inline bool chmin(T& a,T b){if(a>b) {a=b;return true;} return false;}
bool Judge(int i, int j, int h, int w){return i < 0 || j < 0 || i >= h || j >= w;}

constexpr ll INF=numeric_limits<ll>::max() / 4;
constexpr ll MOD=998244353;
const int vi[] = {0, 1, 0, -1}, vj[] = {1, 0, -1, 0};

template<typename... Args>
void LogOutput(Args&&... args){
	stringstream ss;
	((ss << args << ' '), ...);
	cout << ss.str().substr(0, ss.str().length() - 1) << endl;
}
template<typename T>
void LogOutput(vector<vector<T>>& data){for(auto d : data) LogOutput(d);}

int main(){
	ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int h, w;cin>>h>>w;
	vecs s(h);
	rep(i, h) cin>>s[i];
	veci a(h * w, 0);
	rep(i, 1, h - 1) rep(j, 1, w - 1){
		int u = 0;
		rep(k, -1, 2) rep(l, -1, 2){
			if(s[i + k][j + l] == '#'){
				u = 1;
				break;
			}
		}
		if(u) a[i * w + j] = 1;
	}
	auto f = [&](int i, int j){
		return i < 1 || j < 1 || i > h - 2 || j > w - 2;
	};
	veci b;
	queue<pii> q;
	vector dist(h, veci(w));
	auto bfs = [&](){
		rep(i, h) rep(j, w) dist[i][j] = -1;
		dist[1][1] = 0;
		q.emplace(1, 1);
		while(q.size()){
			auto [i, j] = q.front(); q.pop();
			rep(k, -1, 2) rep(l, -1, 2){
				if(!f(i + k, j + l) && a[(i + k) * w + l + j] == 0 && dist[i + k][l + j] == -1){
					dist[i + k][l + j] = dist[i][j] + 1;
					q.emplace(i + k, l + j);
				}
			}
		}
		if(dist[h - 2][w - 2] != -1) return true;
		return false;
	};
	if(!bfs()){
		cout<<0<<endl;
		return 0;
	}
	rep(i, 1, h - 1) rep(j, 1, w - 1){
		if(s[i][j] == '#') continue;
		if((i <= 2 && j <= 2) || (i >= h - 3 && j >= w - 3)) continue;
		rep(k, -1, 2) rep(l, -1, 2) if(!f(i + k, j + l)){
			if(a[(i + k) * w + l + j] == 0){
				b.push_back((i + k) * w + l + j);
				a[(i + k) * w + l + j] = 1;
			}
		}
		if(!bfs()){
			cout<<1<<endl;
			return 0;
		}
		while(b.size()){
			a[b.back()] = 0;
			b.pop_back();
		}
	}
	cout<<2<<endl;
}