#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
const int dx[] = { 1,0,-1,0,1,1,-1,-1 };
const int dy[] = { 0,-1,0,1,1,-1,1,-1 };
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int h, w; cin >> h >> w;
	vector<string>s(h);
	rep(i, h)cin >> s[i];
	auto bfs = [&]()->bool {
		vector<vector<int>> d(h, vector<int>(w, INF));
		queue<pair<int, int>> q;
		q.emplace(1, 1);
		d[1][1] = 0;
		while (!q.empty()) {
			int x = q.front().first;
			int y = q.front().second;
			q.pop();
			rep(i, 8) {
				int nx = x + dx[i];
				int ny = y + dy[i];
				if ((nx <= 0) || (ny <= 0) || (nx >= h - 1) || (ny >= w - 1))continue;
				bool chk = true;
				rep2(j, -1, 2)rep2(k, -1, 2) {
					int nnx = nx + j;
					int nny = ny + k;
					if ('#' == s[nnx][nny])chk = false;
				}
				if (!chk)continue;
				if (chmin(d[nx][ny], d[x][y] + 1)) q.emplace(nx, ny);
			}
		}
		return INF != d[h - 2][w - 2];
	};
	if (!bfs()) {
		cout << 0 << endl;
		return 0;
	}
	rep(i, h)rep(j, w) {
		if (max(i, j) <= 2)continue;
		if (max(h - 1 - i, w - 1 - j) <= 2)continue;
		if ('#' == s[i][j])continue;
		s[i][j] = '#';
		if (!bfs()) {
			cout << 1 << endl;
			return 0;
		}
		s[i][j] = '.';
	}
	cout << 2 << endl;
	return 0;
}