#include<iostream>
using namespace std;

int main(){
  double x[4],y[4],grad1,grad2;
  while(cin >> x[0] >> y[0] >> x[1] >> y[1] >> x[2] >> y[2] >> x[3] >> y[3]){
    grad1 = (y[1] - y[0]) / (x[1] - x[0]);
    grad2 = (y[3] - y[2]) / (x[3] - x[2]);
    //    cout << grad1 << " " << grad2 << endl;
    if((grad1/grad2 == -1) || ( (y[1]==y[0]) && (x[3]==x[2]) ) || ( (y[3]==y[2]) && (x[0]==x[1]) ) )
      cout << "YES" << endl;
    else cout << "NO" << endl;
  }
  return 0;
}