import java.io.*;
import java.util.*;


public class Main_yukicoder707 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int h = sc.nextInt();
		int w = sc.nextInt();
		
		char[][] p = new char[h][];
		for (int i = 0; i < h; i++) {
			p[i] = sc.next().toCharArray();
		}

		double min = Double.MAX_VALUE;
		for (int i = 1; i <= h; i++) {
			min = Math.min(min, d(p, i, 0));
			min = Math.min(min, d(p, i, w + 1));
		}
		for (int j = 1; j <= w; j++) {
			min = Math.min(min, d(p, 0, j));
			min = Math.min(min, d(p, h + 1, j));
		}
		
		pr.printf("%.7f\n", min);
	}

	private static double d(char[][] p, int y, int x) {
		int h = p.length;
		int w = p[0].length;

		double d = 0;
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				if (p[i][j] == '1') {
					d += Math.sqrt((i + 1 - y) * (i + 1 - y) + (j + 1 - x) * (j + 1 - x));
				}
			}
		}

//		pr.printf("%d %d %f\n", y, x, d);
		return d;
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes()));
		pr = new Printer(System.out);

		solve();

//		pr.close();
		pr.flush();
//		sc.close();
	}

	static String INPUT = null;

	private static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
}