#include <bits/stdc++.h>   using namespace std;   const long double PI = 4.0 * atan(1.0);   void EnchomSolve() {     int l;     long double L;     long double ans = 0.0;     long double area;     long double height;     long double help, help2;     scanf( %d , &l);     L = (long double)l;     help = L / sqrt(3.0);     height = sqrt(L * L - help * help);     help = (sqrt(3.0) / 2.0) * L;     area = (help * L) / 2.0;     ans += area * height / 3.0;     scanf( %d , &l);     L = (long double)l;     help = (sqrt(2.0) / 2.0) * L;     height = sqrt(L * L - help * help);     area = L * L;     ans += area * height / 3.0;     scanf( %d , &l);     L = (long double)l;     help = L / (sqrt(2.0 - 2.0 * cos(72.0 * PI / 180.0)));     height = sqrt(L * L - help * help);     help2 = sqrt(help * help - (L / 2.0) * (L / 2.0));     area = L * help2 / 2.0;     area *= 5.0;     ans += area * height / 3.0;     printf( %.10f n , (double)ans);     return;   }   int main() {     EnchomSolve();     return 0;   }   