using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static string[] SList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => ReadLine()).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (h, w) = (c[0], c[1]);
        var p = SList(h);
        var ans = double.MaxValue;
        for (var si = 0; si < h; ++si)
        {
            var left = 0.0;
            var right = 0.0;
            for (var i = 0; i < h; ++i) for (var j = 0; j < w; ++j) if (p[i][j] == '1')
            {
                left += Length(i, j, si, -1);
                right += Length(i, j, si, w);
            }
            ans = Math.Min(ans, Math.Min(left, right));
        }
        for (var sj = 0; sj < w; ++sj)
        {
            var top = 0.0;
            var btm = 0.0;
            for (var i = 0; i < h; ++i) for (var j = 0; j < w; ++j) if (p[i][j] == '1')
            {
                top += Length(i, j, -1, sj);
                btm += Length(i, j, h, sj);
            }
            ans = Math.Min(ans, Math.Min(top, btm));
        }
        WriteLine(ans);
    }
    static double Length(int x1, int y1, int x2, int y2)
    {
        return Math.Sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
    }
}