func_code_string: #include <bits/stdc++.h>   using namespace std;   const double pi = acos(-1.0);   int main() {     int n, r;     cin >> n >> r;     double deg = (1.0 / n) * pi;     double bi = sin(deg);     cout << setiosflags(ios::fixed) << setprecision(10) << (bi / (1 - bi) * r)          << endl;     return 0;   }   