#include<iostream>
#include<cmath>
using namespace std;
const float PaI=3.14;
int main() {
float seed7788;
double av6767676767,b96,c86;
cin >> av6767676767 >> b96 >> c86;
seed7788=av6767676767/b96;
double V_seeesdd = round ( seed7788 * 100 ) / 100;
V_seeesdd = c86;
double v_seed=round(V_seeesdd100)/100;
double V_sedds = pow ((3v_seed)/(4.0PaI),1.0/3);
printf("%.2f",V_sedds);
return 0;
}
