#include <stdio.h>
 
int main(void) {
  int n, i, j;
  double x[4], y[4];
  while(scanf("%lf%lf", &x[0], &y[0]) != EOF) {
    for(i = 1; i < 4; ++i) scanf("%lf%lf", &x[i], &y[i]);
    if((y[1] - y[0]) * (y[3] - y[2]) == -(x[3] - x[2]) * (x[1] - x[0])) printf("YES\n");
    else printf("NO\n");
  }
  return 0;
}
