#include <iostream>
#include <iomanip>
#include <vector>
#include <string>
#include <algorithm>
#include <functional>
using namespace std;

int main() {
	double xa,ya,xb,yb,xc,yc,xd,yd;
	vector<string> r;
	while(cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd)
	{
		if ((xa-xb)*(xc-xd) + (ya-yb)*(yc-yd) == 0)
		{
			r.push_back("YES");
		} else {
			r.push_back("NO");
		}
	}
	for (int i=0; i<r.size(); i++)
	{
		cout << r[i] << endl;
	}
}