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

int main() {
    double n;
    cin>>n;
    vector<double> x(n),y(n),z(n),w(n);
    double sx=0,sy=0,sz=0,sw=0;
    for(int i=0;i<n;i++) {
        cin>>x[i]>>y[i];
        sx+=1.0*x[i];
        sy+=1.0*y[i];
    }
    for(int i=0;i<n;i++) {
        cin>>z[i]>>w[i];
        sz+=1.0*z[i];
        sw+=1.0*w[i];
    }

    double heix=sx/n,heiy=sy/n,heiz=sz/n,heiw=sw/n;

    double s1=0,s2=0;
    for(int i=0;i<n;i++){
        s1+=sqrt((heix-x[i])*(heix-x[i])+(heiy-y[i])*(heiy-y[i]));
        s2+=sqrt((heiz-z[i])*(heiz-z[i])+(heiw-w[i])*(heiw-w[i]));
    }
    double ans=s2/s1;
    cout<<fixed<<setprecision(10)<<ans<<endl;

}