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

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define all(x) (x).begin(),(x).end()
#define foreach(u,v) for(auto (u) : (v))
#define pb push_back
#define mp make_pair
#define mt make_tuple

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pll;
typedef vector<ll> vl;

const int inf = 1e9;
const ll linf = 1LL<<60;
const ll mod = 1e9 + 7;
const double eps = 1e-9;

/*
*/

int main()
{
  int h, w;
  cin >> h >> w;

  string p[h];
  rep(i, h) cin >> p[i];

  double ans = linf;
  rep(x, w){
    int y = -1;
    double tmp = 0;
    rep(i, h) rep(j, w){
      if(p[i][j] == '1'){
        tmp += sqrt((x-j)*(x-j)+(y-i)*(y-i));
      }
    }
    ans = min(ans, tmp);
  }

//  printf("%.12f\n", ans);

  rep(x, w){
    int y = h;
    double tmp = 0;
    rep(i, h) rep(j, w){
      if(p[i][j] == '1'){
        tmp += sqrt((x-j)*(x-j)+(y-i)*(y-i));
      }
    }
    ans = min(ans, tmp);
  }

//  printf("%.12f\n", ans);

  rep(y, w){
    int x = -1;
    double tmp = 0;
    rep(i, h) rep(j, w){
      if(p[i][j] == '1'){
        tmp += sqrt((x-j)*(x-j)+(y-i)*(y-i));
      }
    }
    ans = min(ans, tmp);
  }

//  printf("%.12f\n", ans);

  rep(y, w){
    int x = w;
    double tmp = 0;
    rep(i, h) rep(j, w){
      if(p[i][j] == '1'){
        tmp += sqrt((x-j)*(x-j)+(y-i)*(y-i));
      }
    }
    ans = min(ans, tmp);
  }

  printf("%.12f\n", ans);

  return 0;
}