#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define pl pair<ll, ll>
#define pi pair<int, int>
#define minpq priority_queue<ll, vector<ll>, greater<ll>>
using namespace std;

#if 1
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '['; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "]";}
void _print() {cerr << endl << flush;}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#define debug(x...) cerr << "*["<<__LINE__<<"]\t"<< #x << " = "; _print(x)
#endif

const ll mod = 1e9 + 7;

template<typename T> bool chkmin(T &a, T b){return (b < a) ? a = b, 1 : 0;}
template<typename T> bool chkmax(T &a, T b){return (b > a) ? a = b, 1 : 0;}
ll gcd(ll a, ll b) {if(b == 0){return a;} return gcd(b, a % b);}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n, m; cin >> n >> m;
	vector<string> a(n);
	for (int i = 0; i < n; i ++) cin >> a[i];
	double dp[n + 1][m + 1];
	for (int i = 0; i <= n; i ++){
		for (int j = 0; j <= m; j ++) dp[i][j] = 1e9;
	}
	dp[0][0] = 0;
	for (int i = 0; i <= n; i ++){
		for (int j = 0; j <= m; j ++){
			if (i > 0) chkmin(dp[i][j], dp[i - 1][j] + 1);
			if (j > 0) chkmin(dp[i][j], dp[i][j - 1] + 1);
			for (int pvi = 0; pvi < i; pvi ++){
				for (int pvj = 0; pvj < j; pvj ++){
					bool good = true;
					for (int k = pvi; k < i; k ++){
						for (int p = pvj; p < j; p ++){
							if ((p - pvj) * (i - pvi) < (k - pvi + 1) * (j - pvj) && (p - pvj + 1) * (i - pvi) > (k - pvi) * (j - pvj)){
								if (a[k][p] == '#') good = false;
							}
						}
					}
					if (good) chkmin(dp[i][j], dp[pvi][pvj] + sqrt((i - pvi) * (i - pvi) + (j - pvj) * (j - pvj)));
				}
			}
		}
	}
	cout << fixed << setprecision(10) << dp[n][m] << '\n';
}