ProgBasics02Simple-Operations-P07TriangleArea

import java.util.Scanner;

public class P07TriangleArea{
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        double a =  Double.parseDouble(scanner.nextLine());
        double h =  Double.parseDouble(scanner.nextLine());
        double area = a * h / 2;
        System.out.printf("%.2f", area);

    }
}