#include <iostream>
#include <fstream>
#include <math.h>
using namespace std;

int main() {
	ifstream filein("DATA2.txt");
	ofstream fileout("OUT2.txt");

	double a, b, ans;

	filein >> a >> b;

	ans = (double)(a * a * b / 3);

	ans = ceil(ans);

	fileout << ans << endl;

	filein.close();
	fileout.close();
	return(0);
}