#include <iostream>

using namespace std;

using C = int;
using M = long long;

struct Vec {
    C x, y;
    explicit Vec(C x = 0, C y = 0): x(x), y(y) {}
    Vec operator + (const Vec &v) const {
        return Vec(x + v.x, y + v.y);
    }
    Vec operator - (const Vec &v) const {
        return Vec(x - v.x, y - v.y);
    }
    M operator * (const Vec& v) const {
        return static_cast<M>(x) * v.x + static_cast<M>(y) * v.y;
    }
    M operator % (const Vec &v) const {
        return static_cast<M>(x) * v.y - static_cast<M>(y) * v.x;
    }
};

// Checking whether p, a, b are collinear
bool pol(Vec p, Vec a, Vec b) {
    return (p - a) % (b - a) == 0;
}

// 2S_abc
M ds(Vec a, Vec b, Vec c) {
    return abs((b - a) % (c - a));
}

bool lies_in_triangle(Vec a, Vec b, Vec c, Vec d) {
    bool inside = (ds(d, a, c) + ds(d, a, b) + ds(d, b, c) == ds(a, b, c));
    bool edge = (pol(d, a, c) || pol(d, a, b) || pol(d, b, c));
    return inside && (!edge);
}