#include <bits/stdc++.h>
using namespace std;
int main () {
	int N;
	scanf(" %d", &N);
	double sc[2];
	std::vector<pair<double, double>> X(N);
	for (int pkj = 0; pkj < 2; pkj ++) {
		for (auto& [a, b] : X) scanf(" %lf %lf", &a, &b);
		double x = 0.0, y = 0.0;
		for (auto& [a, b] : X) {
			x += a; y += b;
		}
		x/= N; y /= N;
		sc[pkj] = 0;
		for (auto& [a, b] : X) {
			double dx = a - x, dy = b - y;
			sc[pkj] += sqrt(dx * dx + dy * dy);
		}
	}
	cout << setprecision(20) << sc[1] / sc[0] << endl;
}