#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <deque>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>

#define CK(N, A, B) (A <= N && N < B)
#define REP(i, a, b) for (int i = a; i < b; i++)
#define RREP(i, a, b) for (int i = (b - 1); a <= i; i--)
#define F first
#define S second
#define ll long long

const int INF = 1e9;
const long long LLINF = 1e18;

using namespace std;

int dy[] = {0,1,0,-1};
int dx[] = {1,0,-1,0};
int dy8[] = {0,1,1,1,0,-1,-1,-1};
int dx8[] = {1,1,0,-1,-1,-1,0,1};

/*==================================================*/
/*variable*/
ll H, W;
string s[100];
/*==================================================*/
/*function*/

/*==================================================*/

int main() {
    cin>>H>>W;
    REP(i,0,H){
        cin>>s[i];
    }

    double ans = 300000.0;

    REP(i,0,H+2){
        REP(j,0,W+2){
            if(i != 0 && i != H+1 && j != 0 && j != W+1) continue;

            double t = 0.0;

            REP(k,1,H+1){
                REP(l,1,W+1){
                    if(s[k-1][l-1] == '0') continue;

                    t += sqrt( ((double)i - (double)k)*((double)i - (double)k) +
                               ((double)j - (double)l)*((double)j - (double)l));
                }
            }

            ans = min(ans, t);
        }
    }

    //cout<<ans<<endl;
    printf("%.9f", ans);

    return 0;
}