#include <iostream>
#include <iomanip>
#include <algorithm>

using namespace std;

const long double eps = 1e-6L;

int N;
long double X[102], Y[102];
long double result = 1000000000000.0L;

long double Test(long double a, long double b)
{
	long double resnow = 0;
	for (int i = 1; i <= N; ++i)
		resnow += 1.0L * ((a * X[i] + b) - Y[i]) * ((a * X[i] + b) - Y[i]);
	return resnow;
}
long double Test2(long double a)
{
	long double l1 = -1000000.0L, l2 = 1000000.0L;
	while (l2 - l1 > eps)
	{
		long double mid1 = l1 + (l2 - l1) / 3;
		long double mid2 = l2 - (l2 - l1) / 3;

		if (Test(a, mid1) < Test(a, mid2)) l2 = mid2;
		else                               l1 = mid1;
	}

	return Test(a, l1);
}

int main()
{
	cin.sync_with_stdio(false);

	cin >> N;
	for (int i = 1; i <= N; ++i)
		cin >> X[i] >> Y[i];

	long double pn1 = -1000000.0L, pn2 = 1000000.0L;
	while (pn2 - pn1 > eps)
	{
		long double mid1 = pn1 + (pn2 - pn1) / 3;
		long double mid2 = pn2 - (pn2 - pn1) / 3;

		if (Test2(mid1) < Test2(mid2)) pn2 = mid2;
		else                           pn1 = mid1;
	}

    cout << fixed << setprecision(6) << Test2(pn1) << '\n';
}