TriangleArea

import java.util.Scanner;

public class _02_TriangleArea {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Ax: ");
        double ax = sc.nextDouble();
        System.out.print("Ay: ");
        double ay = sc.nextDouble();

        System.out.print("Bx: ");
        double bx = sc.nextDouble();
        System.out.print("By: ");
        double by = sc.nextDouble();

        System.out.print("Cx: ");
        double cx = sc.nextDouble();
        System.out.print("Cy: ");
        double cy = sc.nextDouble();

        double area = (ax * (by - cy) + bx * (cy - ay) + cx * (ay - by)) / 2 ;

        if ((ax == ay) && (bx == by) && (cx == cy)) {
            System.out.println(0);
        }
        else {
            System.out.print("Area: " + area);
        }
    }

}