func_code_string: #include <bits/stdc++.h>   using namespace std;   int l[7];   int main() {     scanf( %d%d%d , &l[3], &l[4], &l[5]);     double a, A, ap, r, anw = 0;     for (int n = 3; n <= 5; n++) {       a = acos(-1) / n;       A = 1.0 * n / 4 * l[n] * l[n] / tan(a);       ap = A * 2 / n / l[n];       r = ap / cos(a);       anw += A * sqrt(l[n] * l[n] - r * r) / 3;     }     printf( %.10lf , anw);   }   