func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long inf = 1 << 30;   long long m, r;   signed main() {     double ans = 0;     scanf( %d%d , &m, &r);     for (long long i = 1; i <= m; i++) {       double sum = 2 * r;       if (i - 1 != 0) {         sum += 2 * r + sqrt(2) * r;         if (i - 1 >= 2) {           sum += r * (i - 1) * (i - 2) + (i - 2) * 2 * sqrt(2) * r;         }       }       if (m - i != 0) {         sum += 2 * r + sqrt(2) * r;         if (m - i >= 2) {           sum += r * (m - i - 0) * (m - i - 1) + (m - i - 1) * 2 * sqrt(2) * r;         }       }       ans += sum;     }     printf( %.8f n , ans / (m * m));     return 0;   }   