#include<stdio.h>
#include<iostream>
#include<list>
#include<map>
#include<vector>
#include<algorithm>
#include<string.h>
#include<math.h>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) range(i,0,b)
#define debug(x) cout << x << endl;
using namespace std;

int main(){
    double xa, ya, xb, yb, xc, yc, xd, yd;
    while(cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd){
        if( fabs((yb - ya) * (yd - yc) + (xb - xa) * (xd - xc)) < 1e-10){
            cout << "YES" << endl;
        }else{
            cout << "NO" << endl;
        }
    }
}