#include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <memory>
#include <numeric>
#include <set>
#include <stack>
#include <string>
#include <vector>

#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define all(x) (x).begin(), (x).end()
#define MOD 1000000007
#define int long long
using ll = long long;
using namespace std;
const int INF = 1LL << 50;
using P       = pair<int, int>;

template <class T>
bool chmin(T &a, T b) {
    if (a > b) {
        a = b;
        return true;
    } else {
        return false;
    }
}
template <class T>
bool chmax(T &a, T b) {
    if (a < b) {
        a = b;
        return true;
    } else {
        return false;
    }
}

struct Setup {
    Setup() {
        cin.tie(0);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(20);
    }
} SETUP;

double solve(vector<string> &as, int h, int w, int x, int y) {
    double res = 0.0;
    rep(i, 0, h) rep(j, 0, w) {
        int xx = j + 1, yy = i + 1;
        if (as[i][j] == '1') {
            int dx = abs(xx - x), dy = abs(yy - y);
            res += sqrt<int>(dx * dx + dy * dy);
        }
    }
    return res;
}

signed main() {
    int h, w;
    cin >> h >> w;
    vector<string> as(h);
    for (auto &s : as) {
        cin >> s;
    }

    double ans = 1e9;
    rep(i, 1, h + 1) {
        int x = 0, y = i;
        chmin<double>(ans, solve(as, h, w, x, y));
    }
    rep(i, 1, h + 1) {
        int x = w + 1, y = i;
        chmin<double>(ans, solve(as, h, w, x, y));
    }
    rep(i, 1, w + 1) {
        int x = i, y = 0;
        chmin<double>(ans, solve(as, h, w, x, y));
    }
    rep(i, 1, w + 1) {
        int x = i, y = h + 1;
        chmin<double>(ans, solve(as, h, w, x, y));
    }
    cout << ans << endl;
}