func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios::sync_with_stdio(false);     int n, r;     cin >> n >> r;     double alpha = 90.0 - 180.0 / n;     double val = cos(alpha * 3.14159265 / 180.0);     double ans = val * (double)r / (1 - val);     cout << fixed << setprecision(6) << ans << endl;     return 0;   }   