#include <cstdio>
using namespace std;

double xa, ya, xb, yb, xc, yc, xd, yd;
const double eps=0.000000001;

void solve(){
  double x1, y1, x2, y2;
  x1=xb-xa;
  y1=yb-ya;
  x2=xd-xc;
  y2=yd-yc;
  if((x1*x2)+(y1*y2) <= eps) 
    printf("YES\n");
  else
    printf("NO\n");
}

int main(){
  while (scanf("%f %f %f %f %f %f %f %f",
	       &xa, &ya, &xb, &yb, &xc, &yc, &xd, &yd) == 8){
    solve();
  }
}