#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <climits>
 
using namespace std;
 
double EPS = 1e-10;
 
int main() {
    double ax, ay, bx, by, cx, cy, dx, dy;
 
    while( cin >> ax >> ay >> bx >> by >> cx >> cy >> dx >> dy ) {
        bx -= ax; by -= ay;
        dx -= cx; dy -= cy;
 
        if( abs((bx * dx) + (by * dy)) < EPS ) {
            cout << "YES" << endl;
        } else {
            cout << "NO" << endl;
        }
    }
}