#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;
    }
}