#include <string>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

const vector<int> dx = { -1, -1, -1, 0, 0, 1, 1, 1 };
const vector<int> dy = { -1, 0, 1, -1, 1, -1, 0, 1 };

bool reachable(int H, int W, const vector<string>& S) {
	vector<vector<bool> > flag(H - 2, vector<bool>(W - 2, true));
	for (int i = 0; i < H - 2; i++) {
		for (int j = 0; j < W - 2; j++) {
			for (int k = 0; k < 3; k++) {
				for (int l = 0; l < 3; l++) {
					if (S[i + k][j + l] == '#') {
						flag[i][j] = false;
					}
				}
			}
		}
	}
	vector<vector<bool> > vis(H - 2, vector<bool>(W - 2, false));
	auto dfs = [&](auto& dfs, int x, int y) -> void {
		vis[x][y] = true;
		for (int i = 0; i < 8; i++) {
			int tx = x + dx[i];
			int ty = y + dy[i];
			if (0 <= tx && tx < H - 2 && 0 <= ty && ty < W - 2 && flag[tx][ty] && !vis[tx][ty]) {
				dfs(dfs, tx, ty);
			}
		}
	};
	dfs(dfs, 0, 0);
	return vis[H - 3][W - 3];
}

int main() {
	int H, W;
	cin >> H >> W;
	vector<string> S(H);
	for (int i = 0; i < H; i++) {
		cin >> S[i];
	}
	if (!reachable(H, W, S)) {
		cout << 0 << endl;
	}
	else {
		bool flag = false;
		for (int i = 0; i < H; i++) {
			for (int j = 0; j < W; j++) {
				if (S[i][j] == '.' && !(i < 3 && j < 3) && !(i >= H - 3 && j >= W - 3)) {
					S[i][j] = '#';
					if (!reachable(H, W, S)) {
						flag = true;
					}
					S[i][j] = '.';
				}
			}
		}
		cout << (flag ? 1 : 2) << endl;
	}
	return 0;
}