#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
static inline void amin(T &x, U y) {
  if (y < x) x = y;
}
template <typename T, typename U>
static inline void amax(T &x, U y) {
  if (y > x) x = y;
}
const long long int mod = (1000000007);
const long long inf = (long long int)1e18 + 17;
const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};
void solve() {
  double n, ca, sa;
  cin >> n;
  ca = 3.14159265358979323846 / (n);
  sa = 3.14159265358979323846 - ca;
  double cena = ca / 2, l = 0.5, la = sa - (3.14159265358979323846 / 2),
         ans[200];
  for (int i = 1; i <= n / 2; i++) {
    ans[i] = l * (1 + (1 / tan(cena))) * sqrt(2);
    cena += ca;
    l += sin(la);
    la = (3.14159265358979323846 / 2) - la;
    la = sa - (3.14159265358979323846 / 2) - la;
  }
  cena = ca / 2;
  double rans = cos(sa / 2) + sin(sa / 2) / tan(ca / 2);
  rans *= sqrt(2);
  for (int i = 1; i <= n / 2; i++) {
    if (sa - 2 * cena <= (3.14159265358979323846 / 2) &&
        sa + 2 * cena <= 3 * 3.14159265358979323846 / 2) {
      amin(rans, ans[i]);
    }
    cena += ca;
  }
  cout << fixed;
  cout << setprecision(9) << rans << endl;
}
int main() {
  clock_t tt;
  tt = clock();
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  cin >> t;
  for (int i = 1; i <= t; i++) {
    solve();
  }
  tt = clock() - tt;
  double time_taken = ((double)tt) / CLOCKS_PER_SEC;
  return 0;
}
