#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
void test_case() {
  int n;
  cin >> n;
  cout << fixed << setprecision(10) << (1 / tan(PI / (2 * n))) << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int tc;
  cin >> tc;
  for (int tt = 1; tt <= tc; ++tt) {
    test_case();
  }
  return 0;
}
