// includes
#include <cstdio>
#include <cstdint>
#include <iostream>
#include <iomanip>
#include <string>
#include <queue>
#include <stack>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <algorithm>
#include <utility>
#include <functional>
#include <cmath>
#include <climits>
#include <bitset>
#include <list>
#include <random>

// macros
#define ll long long int
#define pb emplace_back
#define mk make_pair
#define pq priority_queue
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())

using namespace std;

//  types
typedef pair<int, int> P;
typedef pair<ll, int> Pl;
typedef pair<ll, ll> Pll;
typedef pair<double, double> Pd;
 
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1e9 + 7;

// solve
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}

int h, w;
string s[51];

double calc(int x, int y){
  double res = 0.;
  for(int i = 0; i < h; i++){
    for(int j = 0; j < w; j++){
      if(s[i][j] == '1')res += sqrt((i+1-x)*(i+1-x)+(j+1-y)*(j+1-y));
    }
  }
  return res;
}

int main(int argc, char const* argv[])
{
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> h >> w;
  rep(i, h)cin >> s[i];
  double res = 1e12;
  for(int i = 1; i <= w; i++){
    res = min(res, calc(0, i));
    res = min(res, calc(h + 1, i));
  }
  for(int i = 1; i <= h; i++){
    res = min(res, calc(i, 0));
    res = min(res, calc(i, w + 1));
  }
  cout << setprecision(12);
  cout << res << endl;
	return 0;
}