// -
#include<iostream>
#include<cstdio>
using namespace std;


main(){
  double xa, ya, xb, yb, xc, yc, xd, yd;
  double A,B;//AAB
  while(scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&xa,&ya,&xb,&yb,&xc,&yc,&xd,&yd)!=EOF){
    // cout << xa << " "<<ya << " " << yd<< endl;
    A=0.0;
    B=0.0;
    if((xa-xb) != 0)A=(ya-yb)/(xa-xb);
    if((xc-xd) != 0)B=(yc-yd)/(xc-xd);
    
    
    if(A*B==-1)cout << "YES"<<endl;
    else if((xa-xb)==0&&B==0)cout << "YES"<<endl;
    else if((xc-xd)==0&&A==0)cout << "YES"<<endl;
    else {cout << "NO"<<endl;}

  }
    
  

  return 0;
}