#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

long double solve(vector<pair<long double, long double>> A) {
    int N = A.size();
    long double gx = 0, gy = 0;
    for (int i = 0; i < N; i++) gx += A[i].first, gy += A[i].second;
    gx /= N, gy /= N;
    for (int i = 0; i < N; i++) A[i].first -= gx, A[i].second -= gy;

    long double res = 0;
    for (int i = 0; i < N; i++) res += hypot(A[i].first, A[i].second);
    return res;
}

int main() {
    int N;
    cin >> N;
    vector<pair<long double, long double>> A(N), B(N);
    for (int i = 0; i < N; i++) cin >> A[i].first >> A[i].second;
    for (int i = 0; i < N; i++) cin >> B[i].first >> B[i].second;
    printf("%.10Lf\n", solve(B) / solve(A));
}