noi1.3.17

	}

}

1.3.17
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
double xa = scan.nextDouble();
double ya = scan.nextDouble();
double xb = scan.nextDouble();
double yb = scan.nextDouble();
double xc = scan.nextDouble();
double yc = scan.nextDouble();
double a = xa - xb ;
double b = ya - yb;
double c = aa + bb;
double d1 = Math.sqrt©;

    double d = xa - xc;
    double e = ya - yc;
    double f = d*d + e*e;
    double d2 = Math.sqrt(f);
    
    double g = xb - xc ;
    double h = yb - yc;
    double i = g * g + h*h;
    double d3 = Math.sqrt(i);
    
    double p = (d1 + d2 + d3)/2;
    double S1 = p*(p - d1)*(p - d2)*(p - d3);
    double S = Math.sqrt(S1);
    System.out.printf("%.2f", S);
	}

}