#include <bits/stdc++.h>
using namespace std;

using db = long double;
using ll = long long;
using vi = vector <int>;
#define op operator
#define pb push_back

const db eps = 1e-12L;
int sgn(db a, db b = 0) {
	a -= b;
	return (a > eps) - (a < -eps);
}

struct poi {
	db x, y;
	auto& r() { return cin >> x >> y; }
	poi op -(poi p) {
		return {x - p.x, y - p.y};
	}
	db dot(poi p) {
		return x * p.x + y * p.y;
	}
};

int main() {
	cout << fixed << setprecision(9);
	ios :: sync_with_stdio(0);

	for(poi a, b, c, d; a.r(); ) {
		b.r(); c.r(); d.r();
		cout << (sgn((b - a).dot(d - c)) == 0 ? "YES" : "NO") << '\n';
	}

	return 0;
}