#include<iostream>
using namespace std;

int main () {
    double x[4],y[4];
    for(i=0;i<4;i++) {
        cin >> x[i] >> y[i];
    }
    if((y[1]-y[2])/(x[1]-x[2]) == (y[3]-y[4])/(x[3]-x[4])) cout << "YES" << endl;
    else cout << "NO" << endl;
}