#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

double calc(int y, int x, const vector<string> &bd) {
  double ret = 0;

  REP (i, bd.size()) REP (j, bd[i].size()) {
    if (bd[i][j] == '1')
      ret += hypot(y - i, x - j);
  }
  
  return ret;
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int h, w;
  cin >> h >> w;

  vector<string> bd(h);
  REP (i, h) cin >> bd[i];

  double ret = 1e100;
  REP (i, w) {
    ret = min(ret, calc(-1, i, bd));
    ret = min(ret, calc(h, i, bd));
  }
  REP (i, h) {
    ret = min(ret, calc(i, -1, bd));
    ret = min(ret, calc(i, w, bd));
  }
  

  cout << fixed << setprecision(12) << ret << endl;
  return 0;
}