func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long second = 0;     int r, m;     cin >> m >> r;     long long koef = 0, koef2 = 0;     for (int i = 1; i <= m; ++i) {       long long lef = i - 2, rig = m - i - 1;       if (lef < 0) lef = 0;       if (rig < 0) rig = 0;       koef2 += i != 1;       koef2 += i != m;       koef += lef + rig;       second += 2;       if (i != 1) second += 2;       if (i != m) second += 2;       second += (lef + 1) * lef;       second += (rig + 1) * rig;     }     long double ans = second + (2 * koef + koef2) * sqrt(2.0);     printf( %.10f n , double(ans / (1LL * m * m) * r));     return 0;   }   