#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=1e9+7;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

int h,w;
vvi a;
 
int main(){
	cin>>h>>w;
	a=vvi(h+2,vi(w+2,-1));
	for(int i=1;i<=h;i++) for(int j=1;j<=w;j++){
		char c;
		cin>>c;
		if(c=='1') a[i][j]=1;
		else a[i][j]=0;
	}
	double res=inf;
	for(int i=0;i<h+2;i++) for(int j=0;j<w+2;j++) if(a[i][j]==-1){
		double tmp=0;
		for(int I=1;I<=h;I++) for(int J=1;J<=w;J++){
			double x=I-i,y=J-j;
			tmp+=sqrt(x*x+y*y)*a[I][J];
		}
		res=min(res,tmp);
	}
	cout<<syosu(9)<<res<<endl;
}