#include<iostream>
#include<string>
#include<cmath>
#include<queue>
#include<vector>
#include<bits//stdc++.h>
#include<functional>
using namespace std;
int main() {
	long double x1,y1,x2,y2,x3,y3,x4,y4;
	while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4){
		if((((y2-y1)*(y4-y3))+((x4-x3)*(x2-x1)))==0) cout<<"YES"<<endl;
		else cout<<"NO"<<endl;
	}
}