#include <iostream>
#include <cstdio>
#include <string>
#include <sstream>
#include <algorithm>
#include <math.h>
#include <map>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>

#define PI 3.14159265359

#define INF 1000000;

#define rep(i, n) for(int i=0; i<n; i++)
#define REP(n) rep(i, n)

typedef long long ll;

using namespace std;


/*
class ElectronicPetEasy
{
public:
	string isDifficult(int st1, int p1, int t1, int st2, int p2, int t2)
	{
		
	}
};
*/



int main()
{
	double xA, yA, xB, yB, xC, yC, xD, yD;
	
	while (cin >> xA >> yA >> xB >> yB >> xC >> yC >> xD >> yD, !cin.eof())
	{
		if((xB-xA)*(xD-xC)+(yB-yA)*(yD-yC) == 0)
		{
			cout << "YES" << endl;
		} else {
			cout << "NO" << endl;
		}
	}
	
	return 0;
}