#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define llong long long

double calc(vector<string> p, int h, int w, int i, int j) {
    double ret;
    rep(a, h) {
        rep(b, w) {
            if(p[a][b] == '1') {
                ret += sqrt((a-i)*(a-i) + (b-j)*(b-j));
            }
        }
    }
    return ret;
}

int main() {
    int h, w;
    cin >> h >> w;
    vector<string> p(h);
    rep(i, h) cin >> p[i];

    double result = 1.0 * INT_MAX;
    rep(i, w) result = min(result, calc(p, h, w, -1, i));
    rep(i, w) result = min(result, calc(p, h, w, h, i));
    rep(i, w) result = min(result, calc(p, h, w, i, -1));
    rep(i, w) result = min(result, calc(p, h, w, i, w));
    printf("%.8f\n", result);
}