#include <iostream>
#include <sstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <climits>
#include <cfloat>
using namespace std;

class Point{
public:
    double y, x;
    Point(){
    }
    Point(double y0, double x0){
        y = y0;
        x = x0;
    }
    Point operator-(const Point& p) const{
        return Point(y-p.y, x-p.x);
    }
    double dot(const Point& p) const{
        return y*p.y + x*p.x;
    }
};

int main()
{
    for(;;){
        Point a, b, c, d;
        if(!(cin >> a.x >> a.y >> b.x >> b.y >> c.x >> c.y >> d.x >> d.y))
            return 0;

        a = a - b;
        c = c - d;
        if(a.dot(c) < 1.0e-10)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
}