#include <bits/stdc++.h>
using namespace std;
const long long N = 5e5;
long long pr(long long a, long long b, long long c) {
  if (b == 0) return 1LL;
  long long ans = 1;
  while (b > 0) {
    if (b % 2) ans = ((ans % c) * (a % c)) % c;
    a = ((a % c) * (a % c)) % c;
    b /= 2;
    a %= c;
    ans %= c;
  }
  return ans;
}
void solve() {
  long long k, m, h, l, r, a, b, c, d, w, mini, maxi = INT_MAX, prev, res;
  double n;
  cin >> n;
  n *= 2.0;
  double y = (double)3.14159265358979323846 / n;
  double ans = tan((3.14159265358979323846 / 2.0) - y);
  cout << fixed << setprecision(10) << ans << endl;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long t = 1;
  cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}
