func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     double m, R;     cin >> m >> R;     double answer = (m * (m + 1) * (m + 2) / 3 - m) * 2;     answer += (sqrt(2.0) - 2) * ((m * m - m) + (m * m - m - (m - 1) * 2));     answer /= (m * m);     answer *= R;     cout << setprecision(7) << answer << endl;     return 0;   }   