#include <iostream>
#include <cstdio>
using namespace std;

int main(){
	double a[8];
	while(cin >> a[0]){
		for(int i = 1;i < 8;i++)cin >> a[i];
		if((a[3]-a[1]) * (a[7]-a[5]) == -1 * (a[2]-a[0]) * (a[6]-a[4]))cout << "YES" << endl;
		else cout << "NO" << endl;
	}
	return 0;
}