#include <iostream>
using namespace std;
int main(void){
  double x[4],y[4];
  while(cin>>x[0]>>y[0]){
    for(int i=1;i<4;i++){
      cin>>x[i]>>y[i];
    }
    if((x[0]==x[1]&&y[2]==y[3])||(x[2]==x[3]&&y[0]==y[1])){
      cout<<"YES\n";
    }else if((y[1]-y[0])*(y[3]-y[2])==-(x[1]-x[0])*(x[3]-x[2])){
      cout<<"YES\n";
    }else{
      cout<<"NO\n";
    }
  }
  return(0);
}