#include <cstdio>
#include <algorithm>
#include <cmath>
using namespace std;
const int N = 1005;
const double PI = acos(-1), eps = 1e-12;
int n;
double maxn, a[N];
bool check (bool opt, double r) {
	double res = 0;
	for (int i = 1; i <= n; i++) {
		res += asin(a[i] / (2 * r));
	}
	if (opt) {
		return res - PI > -eps;
	} else {
		return 2 * asin(maxn / (2 * r)) - res > -eps;
	}
}
double bs (bool opt, double l, double r) {
	while (r - l >= eps) {
		double mid = (l + r) / 2;
		if (check(opt, mid)) {
			l = mid;
		} else {
			r = mid;
		}
	}
	return check(opt, l) ? l : 1e7;
}
int main() {
	scanf ("%d", &n);
	for (int i = 1; i <= n; i++) {
		scanf ("%lf", &a[i]);
		maxn = max (maxn, a[i]);
	}
	printf ("%.8lf\n", min(bs(1, maxn / 2, 1e7), bs(0, maxn / 2, 1e7)));
	return 0;
}