#include <iostream>

using namespace std;

int main() {

	double lenght, width, height, procent, litres;
	cin >> lenght >> width >> height >> procent;

	litres = (lenght *  width * height)* 0.001 * ((100 - procent)/100);

	cout.setf(ios::fixed);
	cout.precision(3);

	cout << litres;

	return 0;
}