zadacha za triugulnik

import java.util.Scanner;

import javax.lang.model.util.ElementScanner6;

class Main {
  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);

    double x1 = Double.parseDouble(scan.nextLine());
    double y1 = Double.parseDouble(scan.nextLine());
    double x2 = Double.parseDouble(scan.nextLine());
    double y2 = Double.parseDouble(scan.nextLine());
    double x3 = Double.parseDouble(scan.nextLine());
    double y3 = Double.parseDouble(scan.nextLine());

    if (x1*(y2-y3)+ x2*(y3-y1) + x3*(y1 - y2) == 0){
      System.out.println("Three points on one line!");
    }else {

    double a = Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
    double b = Math.sqrt((x3 - x1) * (x3 - x1) + (y3 - y1) * (y3 - y1));
    double c = Math.sqrt((x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3));

    double p = (a+b+c) /2;

    double s = Math.sqrt(p*(p-a)*(p-b)*(p-c));
    System.out.printf("s = %2f", s);

    }


  }

}