#include <bits/stdc++.h>
using namespace std;

signed main() {
  ios::sync_with_stdio(false);

  int H, W;
  cin >> H >> W;

  vector<string> P(H);
  for (int i = 0; i < H; ++i) cin >> P[i];

  auto sqr = [](double x) { return x * x; };

  double ans = 1e9;
  for (int i = 0; i < H; ++i) {
    double cost0 = 0, cost1 = 0;
    for (int r = 0; r < H; ++r)
      for (int c = 0; c < W; ++c)
        if (P[r][c] == '1') {
          cost0 += sqrt(sqr(i - r) + sqr(-1 - c));
          cost1 += sqrt(sqr(i - r) + sqr(W - c));
        }
    ans = min(ans, cost0);
    ans = min(ans, cost1);
  }
  for (int i = 0; i < W; ++i) {
    double cost0 = 0, cost1 = 0;
    for (int r = 0; r < H; ++r)
      for (int c = 0; c < W; ++c) 
        if (P[r][c] == '1') {
          cost0 += sqrt(sqr(-1 - r) + sqr(i - c));
          cost1 += sqrt(sqr(H - r) + sqr(i - c));
        }
    ans = min(ans, cost0);
    ans = min(ans, cost1);
  }

  cout << fixed << setprecision(9) << ans << endl;

  return 0;
}