#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000


double dist(int x1, int y1, int x2, int y2) {
	int dx = x2 - x1;
	int dy = y2 - y1;
	int dx2 = dx * dx;
	int dy2 = dy * dy;
	return sqrt(dx2 + dy2);
}

int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
	int H, W;
	cin >> H >> W;
	string S[H];
	rep(i, H) cin >> S[i];
	double ans = INF2;
	REP(x, 0, W + 1) {
		REP(y, 0, H + 1) {
			if (x == 0 && y == 0) continue;
			if (x == 0 && y == H + 1) continue;
			if (x == W + 1 && y == 0) continue;
			if (x == W + 1 && y == H + 1) continue;
			if (0 < x && x <= W && 0 < y && y <= H) continue;
			//cout << x << " " << y << endl;
			double cost = 0;
			rep(i, H) {
				rep(j, W) {
					if (S[i][j] == '1')
						cost += dist(y, x, i + 1, j + 1);
				}
			}
			ans = min(ans, cost);
		}
	}
	cout << fixed;
	cout << setprecision(12) << ans << endl;


    return 0;
}