#include <bits/stdc++.h>
using namespace std;
// #include<atcoder/all>
// using mint = atcoder::modint998244353;
using ld = long double;
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define chmax(a,b) a=max(a,b)
#define chmin(a,b) a=min(a,b)

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int N;
    cin>>N;

    ld S[2]={};
    rep(k,2){
        vector<long> X(N),Y(N);
        rep(i,N)cin>>X[i]>>Y[i];
        
        ld xm=0,ym=0;
        rep(i,N) xm+=X[i],ym+=Y[i];
        xm/=N;
        ym/=N;
        
        rep(i,N) S[k]+=sqrtl((xm-X[i])*(xm-X[i])+(ym-Y[i])*(ym-Y[i]));
    }
    cout<<fixed<<setprecision(15);
    cout<<S[1]/S[0]<<"\n";
    
}