#include <bits/stdc++.h>
#define sz(x) ((int)(x).size())
#define all(x) begin(x), end(x)
#define rep(i, l, r) for (int i = (l), i##end = (r); i <= i##end; ++i)
#define per(i, l, r) for (int i = (l), i##end = (r); i >= i##end; --i)
#ifdef memset0
#define log(...) fprintf(stderr, __VA_ARGS__)
#else
#define log(...) (void(0))
#define endl '\n'
#endif
using namespace std;
using ll = long long;
using lf = long double;
using lll = __int128;
using ull = unsigned long long;

const int N = 1011, T = 200;
const double PI = acos(-1.0);
int a[N], n;
bool err = 0;
bool check(double r) {
  err = 0;
  double sum = 0;
  for (int i = 1; i <= n; ++i) {
    if (a[i] / (r * 2) > 1) err = 1;
    sum += asin(a[i] / (r * 2)) * 2;
  }
  return sum <= 2 * PI;
}
bool check2(double r) {
  // log("check2 r=%.3lf\n", r);
  double sum = asin(a[n] / (r * 2)) * 2;
  // log("s1=%.3lf\n", sum);
  for (int i = 1; i < n; ++i) {
    sum -= asin(a[i] / (r * 2)) * 2;
  }
  return sum <= 0;
}
int main() {
#ifdef memset0
  freopen("E.in", "r", stdin);
#endif
  cin.tie(0)->sync_with_stdio(0);
  cin >> n;
  for (int i = 1; i <= n; ++i) cin >> a[i];
  sort(a + 1, a + n + 1);
  double l = 0, r = 1e9;
  for (int w = 1; w <= T; ++w) {
    double mid = (l + r) / 2;
    if (check(mid)) r = mid;
    else
      l = mid;
  }
  check(l);
  if (!err) printf("%.12lf\n", l);
  else {
    log("Case2!\n");
    r = 1e9;
    for (int w = 1; w <= T; ++w) {

      double mid = (l + r) / 2;
      if (check2(mid)) r = mid;
      else
        l = mid;
    }
    printf("%.12lf\n", l);
  }
  return 0;
}