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

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl

const ll mod = 1e9 + 7;
const ll inf = 1e18;

double calc_dist(double y0, double x0, double y1, double x1){
    double dy = y0 - y1;
    double dx = x0 - x1;
    return sqrt(dy*dy + dx*dx);
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll H, W; cin >> H >> W;

    stringstream ss;
    FOR(i, 0, W+2){
        ss << '.';
    }
    string dot = ss.str();

    vector<string> S(H+2);
    FOR(i, 1, H+1){
        string s;
        cin >> s;
        s = "." + s + ".";
        S[i] = s;
    }
    S[0] = dot;
    S[H+2-1] = dot;

    double ans = inf;
    FOR(i, 0, H+2){
        FOR(j, 0, W+2){
            if(S[i][j]!='.') continue;

            double sum = 0;
            FOR(y, 1, H+1){
                FOR(x, 1, W+1){
                    if(S[y][x]=='1'){
                        sum += calc_dist(i, j, y, x);
                    }
                }
            }
            chmin(ans, sum);
        }
    }

    cout << setprecision(20);
    p(ans);
    
    return 0;
}