#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
using namespace std;
typedef long long ll;
int INF = (1LL << 30) - 1;
int MOD = 1e9+7;    
int H,W;
double calc(vector<string> V,int h,int w){
    double ans = 0;
    rep(i,0,H){
        rep(j,0,W){
            if(V[i][j] == '0')continue;
            double h2 = i + 1,w2 = j + 1;
            ans += sqrt( (h - h2) * (h - h2) + (w - w2) * (w - w2) );
        }
    }
    return ans;
}
main(){
    cin >> H >> W;
    vector<string> V(H);
    rep(i,0,H)cin >> V[i];
    double mini = INF;
    rep(i,1,H+1){
        mini = min(mini, calc(V, i, W+1));
        mini = min(mini, calc(V, i, 0));
    }
    rep(i,1,W+1){
        mini = min(mini, calc(V, 0, i));
        mini = min(mini, calc(V, H+1, i));
    }
    printf("%.9lf\n",mini);
}