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

int main() {
  int h, w;
  cin>>h>>w;
  string s[h];
  for (int i=0; i<h; i++) cin>>s[i];

  vector<pair<int, int> > ps;
  for (int i=1; i<=w; i++) {
    ps.push_back(make_pair(0, i));
    ps.push_back(make_pair(h+1, i));
  }
  for (int i=1; i<=h; i++) {
    ps.push_back(make_pair(i, 0));
    ps.push_back(make_pair(i, w+1));
  }

  double ans = 1e14;

  for (auto p: ps) {
    int y = p.first;
    int x = p.second;
    double tmp = 0.0;
    for (int i=0; i<h; i++) {
      for (int j=0; j<w; j++) {
        if (s[i][j] == '1') {
          tmp += sqrt(pow(y - i - 1, 2) + pow(x - j - 1, 2));
        }
      }
    }
    ans = min(tmp, ans);
  }
  printf("%.6lf\n", ans);
}