#include <bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef long double db;

const db EPS = 1e-9;
const db LINF = 1e18;

int main()
{
	ios::sync_with_stdio(0); 
	cin.tie(0);
	cout << fixed << setprecision(15);
	int n, m;
	cin >> n >> m;
	vector<string> vec(n);
	for (string& row : vec)
		cin >> row;
	vector<VI> pref(n, VI(m + 1));
	FOR(i, 0, n)
		FOR(j, 0, m)
			pref[i][j + 1] = pref[i][j] + (vec[i][j] == '#');
	int vertices = (n + 1) * (m + 1);
	vector<vector<db>> g(vertices, vector<db>(vertices, LINF));
	FOR(i1, 0, n + 1) FOR(j1, 0, m + 1) FOR(i2, 0, n + 1) FOR(j2, 0, m + 1)
	{
		bool ok = true;
		FOR(r, min(i1, i2), max(i1, i2))
		{
			if (j1 == j2)
				break;
			db c1 = j1 + (db)(r - i1) / (i2 - i1) * (j2 - j1);
			db c2 = j1 + (db)(r + 1 - i1) / (i2 - i1) * (j2 - j1);
			if (c1 > c2)
				swap(c1, c2);
			int k1 = clamp((int)(c1 + EPS), 0, m - 1);
			int k2 = clamp((int)(c2 - EPS), 0, m - 1);
			ok &= pref[r][k2 + 1] - pref[r][k1] == 0;
		}
		if (ok)
			g[(m + 1) * i1 + j1][(m + 1) * i2 + j2] = sqrt((i2 - i1) * (i2 - i1) + (j2 - j1) * (j2 - j1));
	}
	vector<db> d(vertices, LINF);
	VI used(vertices);
	d[0] = 0;
	FOR(i, 0, vertices)
	{
		int v = -1;
		FOR(j, 0, vertices)
			if (!used[j] && (v == -1 || d[j] < d[v]))
				v = j;
		used[v] = 1;
		FOR(j, 0, vertices)
			if (!used[j])
				d[j] = min(d[j], d[v] + g[v][j]);
	}
	cout << d[vertices - 1] << "\n";
	cerr << (db)clock() / CLOCKS_PER_SEC << endl;
	return 0;
}