#include<iostream>
using namespace std;

int main(void){
  double x1,x2,x3,x4;
  double y1,y2,y3,y4;
  while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4){
    cout << ((x2-x1) * (x4-x3) + (y2-y1) * (y4-y3)==0?"YES":"NO")<<endl;
  } 
}