#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
using ll = long long;

int h, w;
char p[50][51];

double f(int x, int y) {
    double s = 0;
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            if (p[i][j] == '1') {
                int a = i - x;
                int b = j - y;
                s += sqrt(a * a + b * b);
            }
        }
    }
    return s;
}

int main() {
    cin >> h >> w;

    for (int i = 0; i < h; i++) {
        cin >> p[i];
    }

    double r = 1e100;
    for (int i = 0; i < h; i++) {
        r = min(r, f(-1, i));
        r = min(r, f(h, i));
        r = min(r, f(i, -1));
        r = min(r, f(i, w));
    }

    printf("%.8f\n", r);

    return 0;
}