#include <bits/stdc++.h>

using namespace std;
using ll = long long;
#define int ll
using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;

#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()
#define PB push_back

const ll LLINF = (1LL<<60);
const int INF = (1LL<<30);
const int MOD = 1000000007;

template <typename T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template <typename T> T &chmax(T &a, const T &b) { return a = max(a, b); }
template <typename T> bool IN(T a, T b, T x) { return a<=x&&x<b; }
template<typename T> T ceil(T a, T b) { return a/b + !!(a%b); }
template<class S,class T>
ostream &operator <<(ostream& out,const pair<S,T>& a){
  out<<'('<<a.first<<','<<a.second<<')';
  return out;
}
template<class T>
ostream &operator <<(ostream& out,const vector<T>& a){
  out<<'[';
  REP(i, a.size()) {out<<a[i];if(i!=a.size()-1)out<<',';}
  out<<']';
  return out;
}

int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0};

signed main(void)
{
  cin.tie(0);
  ios::sync_with_stdio(false);

  int h, w;
  cin >> h >> w;
  vector<string> s(h);
  REP(i, h) cin >> s[i];

  double ans = LLINF;
  int x = 1, y = 0;
  while(x <= w) {
    double tmp = 0;
    REP(i, h) REP(j, w) {
      if(s[i][j]=='1')
        tmp += hypot(x-j-1, y-i-1);
    }
    chmin(ans, tmp);
    x++;
  }

  x = 1, y = h+1;
  while(x <= w) {
    double tmp = 0;
    REP(i, h) REP(j, w) {
      if(s[i][j]=='1')
        tmp += hypot(x-j-1, y-i-1);
    }
    chmin(ans, tmp);
    x++;
  }

  x = 0, y = 1;
  while(y <= h) {
    double tmp = 0;
    REP(i, h) REP(j, w) {
      if(s[i][j]=='1')
        tmp += hypot(x-j-1, y-i-1);
    }
    chmin(ans, tmp);
    y++;
  }

  x = w+1, y = 1;
  while(y <= h) {
    double tmp = 0;
    REP(i, h) REP(j, w) {
      if(s[i][j]=='1')
        tmp += hypot(x-j-1, y-i-1);
    }
    chmin(ans, tmp);
    y++;
  }

  cout << fixed << setprecision(15) << ans << endl;

  return 0;
}