#include <bits/stdc++.h>
using namespace std;
const long long int inf = 9e18;
const long double pi = 2 * acos(0.0);
long long int t, n;
long double ans, angle, diff, dis, l, r;
bool check(long double l, long double r) {
  if (abs(r - l) <= (1.0 / 1.0e9)) {
    return false;
  } else {
    return true;
  }
}
void solve() {
  cin >> n;
  angle = pi / n;
  diff = 1.0 / 1.0e5;
  dis = sin(pi / (2 * n));
  ans = 2.0 * (sin((pi - angle) / 2.0) / (sin(angle)));
  l = 0.000000, r = angle;
  while (check(l, r)) {
    long double r1 = r * 1e6;
    long double l1 = l * 1e6;
    long double mid1 = ((2.0 * l1) + r1) / 3.0;
    long double mid2 = (l1 + (2.0 * r1)) / 3.0;
    mid1 /= 1.0e6;
    mid2 /= 1.0e6;
    long double x_left = 1.0e+99, x_right = -1.0e+99, y_left = 1.0e+99,
                y_right = -1.0e+99;
    for (long double j = 0; j < (2.0 * n); j += 1.0) {
      long double px = cos(((pi * j) / n) + mid1);
      long double py = sin(((pi * j) / n) + mid1);
      x_left = min(x_left, px);
      x_right = max(x_right, px);
      y_left = min(y_left, py);
      y_right = max(y_right, py);
    }
    long double ans1 = (max(x_right - x_left, y_right - y_left) / dis) / 2.0;
    x_left = 1.0e+99, x_right = -1.0e+99, y_left = 1.0e+99, y_right = -1.0e+99;
    for (long double j = 0; j < (2.0 * n); j += 1.0) {
      long double px = cos(((pi * j) / n) + mid2);
      long double py = sin(((pi * j) / n) + mid2);
      x_left = min(x_left, px);
      x_right = max(x_right, px);
      y_left = min(y_left, py);
      y_right = max(y_right, py);
    }
    long double ans2 = (max(x_right - x_left, y_right - y_left) / dis) / 2.0;
    if (ans1 <= ans2) {
      r = mid2;
    } else {
      l = mid1;
    }
    ans = min(ans, min(ans1, ans2));
  }
  cout << fixed << setprecision(9) << ans << "\n";
}
int32_t main(void) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  cin >> t;
  while (t--) {
    solve();
  }
}
