#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include <algorithm>
#include <string>

using namespace std;

#define EPS 10e-9

int main(void){

	//内積を計算する
	string str[2] = {"NO", "YES"};
	double x[4], y[4];

	while( true ) {
		if( cin.eof() ) break;
		for( int i = 0; i < 4; i++ ) {
			cin >> x[i] >> y[i];
		}
		double vx[2], vy[2], p;
		vx[0] = x[0] - x[1];
		vx[1] = x[2] - x[3];
		vy[0] = y[0] - y[1];
		vy[1] = y[2] - y[3];
		p = vx[0] * vx[1] + vy[0] * vy[1];
		cout << str[ p < EPS ] << endl;
	}

    return 0;
}