#include <bits/stdc++.h>
using namespace std;

bool is_zero(double f){
	return f < 0.000000001 && f > -0.000000001;
}

int main(){
	double xa,ya,xb,yb,xc,yc,xd,yd;
	while(cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd){
		double yab = ya - yb;
		double xab = xa - xb;
		double ycd = yc - yd;
		double xcd = xc - xd;
		if(is_zero(xab)){
			if(is_zero(ycd)){
				cout << "YES" << endl;
			}
			else{
				cout << "NO" << endl;
			}
			continue;
		}
		if(is_zero(xcd)){
			if(is_zero(yab)){
				cout << "YES" << endl;
			}
			else{
				cout << "NO" << endl;
			}
			continue;
		}
		double p = yab / xab;
		double q = ycd / xcd;
		if(p*q < -0.999999999 && p*q > -1.000000001){
			cout << "YES" << endl;
		}
		else{
			cout << "NO" << endl;
		}
	}
	return 0;
}

