#include "bits/stdc++.h"

using namespace std;
using ll = long long;
const double pi = acos(-1);
#define FOR(i,a,b) for (ll i=(a),__last_##i=(b);i<__last_##i;i++)
#define RFOR(i,a,b) for (ll i=(b)-1,__last_##i=(a);i>=__last_##i;i--)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) RFOR(i,0,n)
#define __GET_MACRO3(_1, _2, _3, NAME, ...) NAME
#define rep(...) __GET_MACRO3(__VA_ARGS__, FOR, REP)(__VA_ARGS__)
#define rrep(...) __GET_MACRO3(__VA_ARGS__, RFOR, RREP)(__VA_ARGS__)
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v) {
	REP(i, v.size()) { if (i)os << " "; os << v[i]; }return os;
}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v) {
	REP(i, v.size()) { if (i)os << endl; os << v[i]; }return os;
}

const ll INF = 1LL << 60;
ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

#define int long long

inline void my_io() {

	std::ios::sync_with_stdio(false);

	std::cin.tie(0);

	cout << fixed << setprecision(16);

	//cout << setprecision(10) << scientific << ans << endl;
}

signed main() {
	ll h, w;
	string s;

	cin >> h >> w;

	vector<pair<ll, ll>> v;

	REP(i, h) {
		cin >> s;

		REP(j, w) {
			if (s[j] == '1') {
				v.push_back(make_pair(i + 1, j + 1));
			}
		}
	}

	vector<pair<ll, ll>> d;

	FOR(i, 1, w + 1) {
		d.push_back(make_pair(0, i));
		d.push_back(make_pair(h + 1, i));
	}

	FOR(i, 1, h + 1) {
		d.push_back(make_pair(i, 0));
		d.push_back(make_pair(i, w + 1));
	}

	double ans = 100000;
	double sum;
	ll x, y;

	REP(i, d.size()) {
		sum = 0;
		REP(j, v.size()) {
			x = abs(d[i].first - v[j].first);
			y = abs(d[i].second - v[j].second);
			sum += sqrt(x * x + y * y);
		}
		ans = min(ans, sum);
	}

	cout << setprecision(10) << scientific << ans << endl;
}