#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1000005;
const int SQRTN = 1003;
const int LOGN = 22;
const double PI = acos(-1);
const int INF = 1e9;
int MOD = 1000000007;
const int FMOD = 998244353;
const double eps = 1e-9;
long long gcd(long long a, long long b) {
  if (a == 0) return (b);
  return (gcd(b % a, a));
}
long long lcm(long long a, long long b) { return (a / gcd(a, b) * b); }
bool isprime(long long x) {
  if (x == 1) return (false);
  for (long long i = 2; i * i <= x; i++) {
    if (x % i == 0) return (false);
  }
  return (true);
}
long long dp[1000000];
int div(long long i) {
  long long count = 0;
  for (long long j = 1; j * j <= i; j++) {
    if (i % j == 0) {
      count++;
      if (i / j != j) count++;
    }
  }
  return (count);
}
void solve() {
  long long n;
  cin >> n;
  double ans = 1 / tan(PI / (2 * n));
  cout << fixed << setprecision(16) << ans << "\n";
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t;
  cin >> t;
  while (t--) {
    solve();
  }
  return (0);
}
