#include<iostream>
#include<string>
#include<cmath>
#include<queue>
#include<vector>
#include<functional>
using namespace std;
int main() {
	double x1, y1, x2, y2, x3, y3, x4, y4;
	cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4;
	double a = 99999, b = 99999;
	if (x2 - x1 != 0) {
		a = (y2 - y1) / (x2 - x1);
	}
	if (x4 - x3 != 0) {
		b = (y4 - y3) / (x4 - x3);
	}
	if (a == b) cout << "YES" << endl;
	else cout << "NO" << endl;
}