#include <iostream>
#include <algorithm>
#include <cmath>

using namespace std;

const long double PI = 3.14159265;

struct Vec {
	long double x, y;

	Vec norm() const {
		return { x / len(), y / len() };
	}

	Vec operator+ (const Vec &rhs) const {
		return {x + rhs.x, y + rhs.y};
	}

	Vec operator- (const Vec &rhs) const {
		return { x - rhs.x, y - rhs.y };
	}

	long double operator% (const Vec & rhs) const {
		return x * rhs.x + y * rhs.y;
	}

	long double operator^ (const Vec & rhs) const {
		return x * rhs.y - rhs.x * y;
	}

	template <typename T>
	Vec operator*(T rhs) const {
		return { x * rhs, y * rhs };
	}

	template <typename T>
	Vec operator/(T rhs) const {
		return { x / rhs, y / rhs };
	}

	long long len2() const {
		return 1LL * x * x + 1LL * y * y;
	}

	long double len() const {
		return sqrt(x * x + y * y);
	}
};

long double get_angle(Vec v1, Vec v2) {
	return atan2(v1 ^ v2, v1 % v2);
}

int main() {
	//freopen("goat1.in", "r", stdin);
	//freopen("goat1.out", "w", stdout);

	Vec p1, p2, p3, p4;
	cin >> p1.x >> p1.y;
	cin >> p2.x >> p2.y;
	cin >> p3.x >> p3.y;
	cin >> p4.x >> p4.y;

	p1 = p1 - p2;
	p3 = p3 - p2;
	p4 = p4 - p2;

	long double x1 = (p4 ^ p1), x2 = (p4 ^ p3);
	if (abs((p1 % p4) / abs(p1 % p4) - (p3 % p4) / abs(p3 % p4)) < 0.00000001) {
		cout << "YES";
	}
	else {
		cout << "NO";
	}


	return 0;
}