#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

struct Point{

    ll x, y;

    Point( ll x=, ll y= ): x(x), y(y){}

};

typedef Point Vector;

Point p[];

Vector operator -(const Vector a, const Vector b ){

    return Vector( a.x-b.x, a.y-b.y );

}

ll Cross( Vector a, Vector b ){

    return a.x*b.y - a.y*b.x;

}

int main(){

    ios::sync_with_stdio();

    cin.tie();

    cout.tie();

    ll x1, y1, x2, y2, x3, y3;

    while( cin >> x1 >> y1 ){

        cin >> x2 >> y2 >> x3 >> y3;

        p[] = Point(x1, y1);

        p[] = Point(x2, y2);

        p[] = Point(x3, y3);

        ll ans = Cross( p[]-p[], p[]-p[] )*;

        if( ans< ) ans = -ans;

        cout << ans <<endl;

    }

    return ;

}