#include <iostream>
#include <cstdio>
#include <complex>
using namespace std;

int main()
{
  complex<double> a[4];
  double x, y;
  while (scanf("%lf %lf ", &x, &y) == 2) {
    a[0] = complex<double>(x, y); 
    for (int i = 1; i < 4; i++) {
      scanf("%lf %lf ", &x, &y);
      a[i] = complex<double>(x, y);
    }
    
    if ((a[1].real() - a[0].real()) * (a[3].real() - a[2].real()) + (a[1].imag() - a[0].imag()) * (a[3].imag() - a[2].imag()) == 0) {
      cout << "YES" << endl;
    } else {
      cout << "NO" << endl;
    }
  }
  return 0;
}