#include <cstdio>

using namespace std;

int main() {
  double xA, yA, xB, yB, xC, yC, xD, yD;
  while (scanf("%lf%lf%lf%lf%lf%lf%lf%lf", &xA, &yA, &xB, &yB, &xC, &yC, &xD, &yD) == 8) {
    double a = xB-xA, b = yB-yA, c = xD-xC, d = yD-yC;
    puts(a * c + b * d == 0 ? "YES" : "NO");
  }
  return 0;
}