#include<cstdio>
#include<cstring>
#include<vector>
#include<queue>
#include<stack>
#include<algorithm>
#include<cmath>
#include<climits>
#include<string>
#include<set>
#include<numeric>
#include<map>
#include<iostream>
using namespace std;
#define rep(i,n) for(int i = 0;i<((int)(n));i++)
#define reg(i,a,b) for(int i = ((int)(a));i<=((int)(b));i++)
#define irep(i,n) for(int i = ((int)(n)-1);i>=0;i--)
#define ireg(i,a,b) for(int i = ((int)(b));i>=((int)(a));i--)
typedef long long ll;
typedef pair<ll, ll> mp;
ll mod = 1e9+7;
ll inf = 1e18;

//AC

ll h,w;
string p[100];
double ans=999999;

double dist(ll x,ll y){
	double d=0;
	reg(i,1,h){
		reg(j,1,w){
			if(p[i][j-1]=='1'){
				d+=sqrt(pow(x-j,2)+pow(y-i,2));
				// cout<<d<<endl;
			}
		}
	}
	return d;
}

int main(void){
	cin>>h>>w;
	reg(i,1,h){
		cin>>p[i];
	}
	reg(i,1,w)ans=min(ans,dist(i,0));
	reg(i,1,w)ans=min(ans,dist(i,h+1));
	reg(i,1,h)ans=min(ans,dist(0,i));
	reg(i,1,h)ans=min(ans,dist(w+1,i));
	cout<<ans<<endl;
	return 0;
}