#include <iostream>
#include <complex>
#include <cmath>
using namespace std;
typedef complex<double> C;

#define EPS (1e-8)
#define EQ(a,b) (abs((a)-(b)) < EPS)

double dot(C a, C b) {
	return a.real() * b.real() + a.imag() * b.imag();
}

double xa, ya, xb, yb, xc, yc, xd, yd;

void solve() {
	C a(xa, ya), b(xb, yb), c(xc, yc), d(xd, yd);
	
	if (EQ(dot(a-b, c-d), 0.0)) {
		cout<<"YES";
	} else {
		cout<<"NO";
	}
	cout<<endl;
}

int main(int argc, const char *argv[]) {
	while (cin>>xa>>ya>>xb>>yb>>xc>>yc>>xd>>yd) {
		solve();
	}
	return 0;
}