#include <iostream>
#include <stdio.h>
#include <string>
#include <vector>
#include <math.h>
using namespace std;
double GetDist(int x,int y,vector<pair<int,int>> &myV)
{
	int i;
	double dist=0;
	for (i=0;i<myV.size();i++){
		int x1=myV[i].first;
		int y1=myV[i].second;
		dist+=sqrt((double)(x-x1)*(x-x1)+(y-y1)*(y-y1));
	}
	return dist;
}
int main(int argc, char* argv[])
{
	int H,W;
	cin>>H>>W;
	vector<pair<int,int>> myV;
	int i,j;
	for (i=1;i<=H;i++){
		string S;
		cin>>S;
		for (j=0;j<S.size();j++){
			if (S[j]=='1'){
				myV.push_back(make_pair(i,j+1));
			}
		}
	}
	double dist;
	double MaxDist=1e9;
	i=0;
	for (j=1;j<=H;j++){
		dist=GetDist(i,j,myV);
		if (MaxDist>dist){
			MaxDist=dist;
		}
	}
	i=H+1;
	for (j=1;j<=H;j++){
		dist=GetDist(i,j,myV);
		if (MaxDist>dist){
			MaxDist=dist;
		}
	}
	
	j=0;
	for (i=1;i<=W;i++){
		dist=GetDist(i,j,myV);
		if (MaxDist>dist){
			MaxDist=dist;
		}
	}
	j=H+1;
	for (i=1;i<=W;i++){
		dist=GetDist(i,j,myV);
		if (MaxDist>dist){
			MaxDist=dist;
		}
	}
	printf("%.8lf\n",MaxDist);
	return 0;
}