#include<stdio.h>
#include <algorithm>
#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <iostream>
#include <iterator>
#include <list>
#include <map>     
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <iomanip>
#include <stack>
#include <string>
#include <vector>
using namespace std;
#define ll long long
#define ld long double
#define rep(a,t) for(int a=0;a<t;a++) 
#define forever while(true)
#define Sort(a) sort(a.begin(),a.end())
#define Reverse(a) reverse(a.begin(),a.end())
#define pb push_back
int main()
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	double xa, ya, xb, yb, xc, yc, xd, yd;
	while (cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd) {
		if (xa == xb) {
			if (yc == yd) {
				cout << "YES" << endl;
			}
			else {
				cout << "NO" << endl;
			}
			continue;
		}
		if (xc == xd) {
			if (ya == yb) {
				cout << "YES" << endl;
			}
			else {
				cout << "NO" << endl;
			}
		}
		double katamuki[2];
		katamuki[0] = (yb - ya) / (double)(xb - xa);
		katamuki[1] = (yd - yc) / (double)(xd - xc);
		if (katamuki[0] * katamuki[1] == -1) {
			cout << "YES"<<endl;
}
		else {
			cout << "NO" << endl;
		}
	}
	return 0;
}
