#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 1000000007
#define MAX_N 5001
#define EPS 1e-10

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<string, ll> PS;
typedef vector<ll> V;

double x[10], y[10];

int main(){
	while (cin>>x[0]>>y[0]){
		FOR(i, 1, 4) cin >> x[i] >> y[i];
		if (abs((x[1] - x[0])*(x[3] - x[2])
			+ (y[1] - y[0])*(y[3] - y[2])) < EPS){
			cout << "YES\n";
		}
		else cout << "NO\n";
	}
}