#include <bits/stdc++.h>
#define range(i,a,b) for(int (i)=(a);(i)<(b);(i)++)
#define rep(i,n) range(i,0,n)
using namespace std;

typedef complex<double> P;
bool ip(P a,P b){return (a.real()*b.real()+a.imag()*b.imag())==0.0;}

int main(void){
	P p[4];
	while(1){
		rep(i,4){
			double x,y;
			cin >> x >> y;
			p[i]={x,y};
		}
		if(cin.eof()) break;
		if(ip(p[1]-p[0],p[3]-p[2]))
			puts("YES");
		else
			puts("NO");
	}
	return 0;
}