#define _USE_MATH_DEFINES

#include <cmath>
#include <iomanip>
#include <iostream>

int main() {
  long double H, R;
  std::cin >> H >> R;
  std::cout << std::fixed << std::setprecision(15) << 30574.154032453271139L / (912.70L * 548.36L * 548.36L) * H * R * R << "\n";
}