#define pb push_back
#define ff first
#define ss second
#define fori(n) for (int i = 0; i < n; i++)
#define forj(n) for (int j = 0; j < n; j++)

struct point {
    double x, y;
};
struct line {
    double A, B, C;
};
double dist(point a, point b) {
    return sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y));
}
double dist_line(point p, line l) {
    return abs(l.A * p.x + l.B * p.y + l.C) / (sqrt(l.A * l.A + l.B * l.B));
}
point make_point(double x, double y) {
    point a;
    a.x = x;
    a.y = y;
    return a;
}
line make_line_byPoint(point a, point b) {
    line ans;
    ans.A = a.y - b.y;
    ans.B = b.x - a.x;
    ans.C = a.x * b.y -   b.x * a.y;
    return ans;
}
line make_line(double A, double B, double C) {
    line a;
    a.A = A;
    a.B = B;
    a.C = C;
    return a;
}
point intersect(point a, point b, line lin) {
    point kek = b;
    kek.x -= a.x;
    kek.y -= a.y;
    double l = 0.0, r = 1.0;
    double m1, m2;
    double d1, d2;
    fori(1000) {
        m1 = l + (r - l) / 3;
        m2 = r - (r - l) / 3;
        d1 = dist_line(make_point(a.x + kek.x * m1, a.y + kek.y * m1), lin);
        d2 = dist_line(make_point(a.x + kek.x * m2, a.y + kek.y * m2), lin);
        if (d1 > d2) l = m1;
        else r = m2;
    }
    return make_point(a.x + kek.x * l, a.y + kek.y * l);
}
double sq(vector < point > a) {
    double res = 0;
    int j;
    fori(a.size()) {
        if (i == a.size() - 1) j = 0;
        else j = i + 1;
        res += (a[i].x - a[j].x) * (a[i].y + a[j].y);
    }
    return abs(res) / 2.0;
}
double eps;
vector < line > lines;
double ans = 0;
void kek(int ind, vector < point > cur) {
    if (ind == lines.size()) {
        ans = max(ans, sq(cur));
        return ;
    }
    vector < pair < int, point > > bubs;
    point b;
    for (int i = 0; i < cur.size(); i++) {
        b = intersect(cur[i], cur[(i + 1) % cur.size()], lines[ind]);
        if (dist_line(b, lines[ind]) > eps) continue;
        if (bubs.size() == 0) {
            bubs.pb({i, b});
            continue;
        }
        if (dist(bubs.back().ss, b) > eps) {
            bubs.pb({i, b});
        }
    }
    if (bubs.size() == 0) {
        kek(ind + 1, cur);
        return ;
    }
    if (bubs.size() == 1) {
        //cout << "on line you f** idiot";
        kek(ind + 1, cur);
        exit(0);
    }
    if (bubs.size() != 2) {
        cout << "something wrong....";
        while (true) ;
        /// если сюда зайдет, то получим tl из-за бесконечного цикла
        exit(0);
    }
    int i1 = bubs[0].ff;
    int i2 = bubs[1].ff;
    vector < point > a1;
    a1.pb(bubs[0].ss);
    for (int i = i1 + 1; i <= i2; i++) a1.pb(cur[i]);
    a1.pb(bubs[1].ss);
    kek(ind + 1, a1);
    a1 = {};

    a1.pb(bubs[1].ss);
    for (int i = i2 + 1; i < cur.size(); i++) a1.pb(cur[i]);
    for (int i = 0; i <= i1; i++) a1.pb(cur[i]);
    a1.pb(bubs[0].ss);
    kek(ind + 1, a1);
}
int main() {
    cout << fixed << setprecision(40);
    eps = 0.0000000001;

    vector < pair < pair < int, int >, pair < int, int > > > inp;
    inp = {
    {{50, 32}, {-13, 43}},
    {{23, -34}, {80, 55}}
    };
    fori(inp.size()) {
        point p1 = make_point(inp[i].ff.ff, inp[i].ff.ss);
        point p2 = make_point(inp[i].ss.ff, inp[i].ss.ss);
        lines.pb(make_line_byPoint(p1, p2));
    }
    vector < point > beg;
    beg.pb(make_point(-50, -50));
    beg.pb(make_point(-50, 50));
    beg.pb(make_point(50, 50));
    beg.pb(make_point(50, -50));
    kek(0, beg);
    cout << ans;
}