#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <cassert>
#include <iostream>
#include <cctype>
#include <sstream>
#include <string>
#include <list>
#include <vector>
#include <queue>
#include <set>
#include <stack>
#include <map>
#include <utility>
#include <numeric>
#include <algorithm>
#include <bitset>
#include <complex>
#include <fstream>
using namespace std;
typedef long long ll;
const double EPS = 1e-9;
typedef vector<int> vint;
typedef pair<int, int> pint;
#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for(int i = x; i < n; i++)
template<class T> T RoundOff(T a){ return int(a+.5-(a<0)); }
template<class T, class C> void chmax(T& a, C b){ if(a < b) a = b; }
template<class T, class C> void chmin(T& a, C b){ if(b < a) a = b; }
template<class T, class C> pair<T, C> mp(T a, C b){ return make_pair(a, b); }
 
struct  P{
    double x, y;
};
 
int main()
{
    P p[4];
    while(cin >> p[0].x >> p[0].y >> p[1].x >> p[1].y >> p[2].x >> p[2].y >> p[3].x >> p[3].y)
    {
        // y1 / x1 = -x2 / y2;
        // y1 * y2 = -x1 * x2;
        
        double x1 = p[0].x - p[1].x, x2 = p[2].x - p[3].x;
        double y1 = p[0].y - p[1].y, y2 = p[2].y - p[3].y;
        
        if(!x1 && !y2)      cout << "YES" << endl;
        else if(!y1 && !x2) cout << "YES" << endl;
        else if(abs(y1 * y2 + x1 * x2) <= EPS) cout << "YES" << endl;
        else    cout << "NO" << endl;
        
    }
}