import java.util.Scanner;

public class Geometry

$\{$

$/**$

Computes the area of a triangle

@param x$1$ the x$-$coordinate of the first corner

@param y$1$ the y$-$coordinate of the first corner

@param x$2$ the x$-$coordinate of the second corner

@param y$2$ the y$-$coordinate of the second corner

@param x$3$ the x$-$coordinate of the third corner

@param y$3$ the y$-$coordinate of the third corner

@return the area of the triangle