#include <bits/stdc++.h>
#define rep(i,l,n) for(int i=l;i<n;i++)
#define rer(i,l,n) for(int i=l;i<=n;i++)
#define all(a) a.begin(),a.end()
#define o(a) cout<<a<<endl
#define pb(a) push_back(a)
#define mk(a,b) make_pair(a,b)
#define fi first
#define se second
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;

double dot_product(double x1,double y1,double x2,double y2){
	return x1*x2+y1*y2;
}

int main(){
	while(1){
		double xa,ya,xb,yb,xc,yc,xd,yd;
		cin>>xa>>ya>>xb>>yb>>xc>>yc>>xd>>yd;
		if(cin.eof()) break;
		if(abs(dot_product(xa-xb,ya-yb,xc-xd,yc-yd))<1e-10) o("YES");
		else o("NO");
	}
}