import java.io.*;

public class DWITE2 {
	public static void main (String [] args) throws IOException {
		BufferedReader inBuff = new BufferedReader(new FileReader("DATA2.txt"));
		PrintWriter outPrint = new PrintWriter(new FileWriter("OUT2.txt"));
		
		double length = Double.parseDouble(inBuff.readLine());
		double height = Double.parseDouble(inBuff.readLine());
		double base = length*length;
		double shit = (base*height)/3;
		int volume = (int)((base*height)/3);
		if (shit+0.5>volume){
			volume++;
		}
		
		//String check = volume;
		//int pos = check.indexOf(".");
		//String character = check.substring()
		
		
		outPrint.println(volume);
		outPrint.close();		
	}
}