#include<iostream>
using namespace std;
struct P{
  double x;
  double y;
};
int main(){
  P a,b,c,d;
  while(cin >>a.x>>a.y>>b.x>>b.y>>c.x>>c.y>>d.x>>d.y){
    P v,w;
    v.x = a.x-b.x;
    v.y = a.y-b.y;
    w.x = c.x-d.x;
    w.y = c.y-d.y;
    if(v.x*w.x+v.y*w.y == 0) cout <<"YES"<<endl;
    else cout <<"NO"<<endl;
  }
  return 0;
}