#include <bits/stdc++.h>
using namespace std;
double PI = acos(-1);
double pre[500];
int caled[500];
double getRad(int n) {
  double theta = PI - (n - 2) * PI / n;
  double x = 0;
  double y = 0;
  double cth = 0;
  double r = 1;
  for (int i = 0; i < n; i++) {
    cth += theta;
    x += cos(cth);
    y += sin(cth);
    double dist = sqrt(x * x + y * y);
    r = max(r, dist / 2);
  }
  return r;
}
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    n *= 2;
    if (caled[n]) {
      cout << fixed << setprecision(10) << pre[n] << endl;
      continue;
    }
    double r = getRad(n);
    double Theta = 2 * PI / n;
    double th = 0;
    double ans = 100010;
    while (th < 2 * PI) {
      double x = r * cos(th);
      double y = r * sin(th);
      double mnx = x, mxx = x;
      double mny = y, mxy = y;
      for (int i = 0; i < n; i++) {
        x = r * cos(Theta * i + th);
        y = r * sin(Theta * i + th);
        mnx = min(mnx, x);
        mxx = max(mxx, x);
        mny = min(mny, y);
        mxy = max(mxy, y);
      }
      double cur = max(mxx - mnx, mxy - mny);
      ans = min(ans, cur);
      th += 2 * PI / 1000;
    }
    caled[n] = 1;
    pre[n] = ans;
    cout << fixed << setprecision(10) << ans << endl;
  }
}
