#include <bits/stdc++.h>
using namespace std;
const long long int N = 2e5 + 5;
void solve() {
  long long int n;
  cin >> n;
  double ans, pi = 3.14159265358979323846;
  double rad = (2.0 * sin(pi / (2.0 * (double)n)));
  ans = (cos(pi / (4.0 * n))) / sin(pi / (2.0 * (double)n));
  cout << fixed << setprecision(15) << ans << '\n';
}
signed main() {
  ios_base::sync_with_stdio(0), cin.tie(NULL), cout.tie(NULL);
  long long int t = 1;
  cin >> t;
  while (t--) {
    solve();
  }
}
