void input() {
    for (int i = 0; i < n; i++) {
        double x, y;
        scanf("%lf%lf", &x, &y);
        c1.push_back(Point(x, y));
    }
    for (int i = 0; i < m; i++) {
        double x, y;
        scanf("%lf%lf", &x, &y);
        c2.push_back(Point(x, y));
    }
}
double area(Convex a) {
    double sum = 0;
    a.push_back(a[0]);
    for (int i = 0; i < a.size() - 1; i++) {
        sum += cross(a[i], a[i+1]);
    }
    return sum / 2.0;
}