#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
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; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

int main() {
	int H, W;
	cin >> H >> W;
	vector<string> grid(H);
	REP(i, H) cin >> grid[i];
	vector<pii> pred; // (i, j)
	REP(i, H) {
		pred.emplace_back(i, -1);
		pred.emplace_back(i, W);
	}
	REP(i, W) {
		pred.emplace_back(-1, i);
		pred.emplace_back(H, i);
	}
	double ans = INF;
	for (auto [y, x] : pred) {
		double cur = 0;
		REP(i, H) REP(j, W) if (grid[i][j] == '1') cur += hypot(i - y, j - x);
		chmin(ans, cur);
	}
	printf("%.16f\n", ans);
}