#include <bits/stdc++.h>
using namespace std;
bool isPrime(int n) {
  if (n <= 1) return false;
  if (n <= 3) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  for (int i = 5; i * i <= n; i = i + 6)
    if (n % i == 0 || n % (i + 2) == 0) return false;
  return true;
}
void solve() {
  int n;
  cin >> n;
  long double pi = 2.0 * acos(0.0), ans, x;
  x = pi / (long double)(2.0 * n);
  ans = tan(x);
  cout << fixed << setprecision(9) << 1.0 / ans << '\n';
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  int t;
  cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}
