#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using ll =  long long ;
using P = pair<int,int> ;
const int INF = 1e9;
const int MOD = 1000000007;

int main(){
    int h,w;
    cin >> h >> w;
    vector<string> moji(h);
    rep(i,h) cin >> moji[i];
    double ans = INF;
    rep(loc,h){
        double res1 = 0,res2 = 0;
        rep(i,h)rep(j,w){
            if(moji[i][j] == '0') continue;
            res1 += sqrt( (i-loc) * (i-loc) + (j+1) * (j+1) );
            res2 += sqrt( (i-loc) * (i-loc) + (w-j) * (w-j) );
        }
        ans = min(ans,min(res1,res2));
    }
    rep(loc,w){
        double res1 = 0,res2 = 0;
        rep(i,h)rep(j,w){
            if(moji[i][j] == '0') continue;
            res1 += sqrt( (i+1) * (i+1) + (j-loc) * (j-loc) );
            res2 += sqrt( (h-i) * (h-i) + (j-loc) * (j-loc) );
        }
        ans = min(ans,min(res1,res2));
    }
    cout << setprecision(20) << ans << endl;
    return 0;
}