#include <iostream>
#include <algorithm>
#include <cassert>
#include <cctype>
#include <cstdio>
#include <math.h>
#include <map>
#include <queue>
#include <string>
using namespace std;

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

int main(){
	while(cin>>xa>>ya>>xb>>yb>>xc>>yc>>xd>>yd){
		if((xb-xa)*(xd-xc)+(yb-ya)*(yd-yc)==0)cout<<"YES"<<endl;
		else cout<<"NO"<<endl;
	}
}