#include <cstdio>
#include<iostream>

using namespace std;
 
int main(void){

	long double xa,ya,xb,yb,xc,yc,xd,yd;

	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;
	}

    return 0;
}