#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;   }   