#include <bits/stdc++.h>
using namespace std;
const int MOD = 998244353;
const int N = 2000005;
const double PI = 4 * atan(1);
const double eps = 1e-7;
const long long oo = 1e10;
const int K = 205;
long long t;
long double angle, angle2;
long double val;
long double a, b;
long double l, r;
long double m1, m2;
long long n;
void fun(long double phi) {
  long double ansx1 = 0.0;
  long double ansx2 = 0.0;
  long double ansy1 = 0.0;
  long double ansy2 = 0.0;
  for (int i = 0; i < n; i++) {
    ansx1 =
        (ansx1 > b * cos(i * angle + phi) ? ansx1 : b * cos(i * angle + phi));
    ansx2 =
        (ansx2 < b * cos(i * angle + phi) ? ansx2 : b * cos(i * angle + phi));
    ansy1 =
        (ansy1 > b * sin(i * angle + phi) ? ansy1 : b * sin(i * angle + phi));
    ansy2 =
        (ansy2 < b * sin(i * angle + phi) ? ansy2 : b * sin(i * angle + phi));
  }
  val = (ansx1 - ansx2 > ansy1 - ansy2 ? ansx1 - ansx2 : ansy1 - ansy2);
}
int main() {
  cin >> t;
  while (t--) {
    scanf("%lld", &n);
    n *= 2;
    angle = 2 * PI / (long double)(1.0 * n);
    b = 0.5 / sin(angle / 2);
    l = 0;
    r = 2 * PI / n;
    for (int i = 0; i < 100; i++) {
      m1 = l + (r - l) / 3;
      m2 = r - (r - l) / 3;
      val = 0;
      fun(m1);
      long double f1 = val;
      val = 0;
      fun(m2);
      long double f2 = val;
      if (f1 > f2)
        l = m1;
      else
        r = m2;
    }
    val = 0;
    fun(l);
    a = val;
    printf("%0.8Lf\n", a);
  }
  return 0;
}
