#include<iostream>
using namespace std;

int main(){

	double xa, ya, xb, yb, xc, yc, xd, yd;

	while (cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd){
		if ((yb-ya)*(yd-yc)==-((xd-xc)*(xb-xa)))
		{
			cout << "YES" << endl;
		}
		else
		{
			cout << "NO" << endl;
		}

	}
}