#include <iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
#include<random>
using namespace std;
int inf = 1e9;

int main() {

  vector<double> x(4);
  vector<double> y(4);
  while( cin >> x[0] >> y[0] >> x[1] >> y[1] >> x[2] >> y[2] >> x[3] >> y[3] ){
    double ax = x[1]-x[0];
    double ay = y[1]-y[0];
    double bx = x[3]-x[2];
    double by = y[3]-y[2];
    if( ax*bx + ay*by < 0.001 ){
      cout << "YES" << endl;
    }else cout << "NO" << endl;

  }

  return 0;
}




// EOF