#include <iostream>
#include <cmath>
using namespace std;
int main(){
	double a[8];
	while(cin >> a[0]){
		for(int i=1;i<8;i++) cin >> a[i];
		double b[4] = {a[2]-a[0],a[3]-a[1],a[6]-a[4],a[7]-a[5]};
		if(abs(b[0]*b[2]+b[1]*b[3])<0.0000001) cout << "YES" << endl;
		else cout << "NO" << endl;
	}
}