#include <iostream>
#include <cstdio>
using namespace std;

int main(){
	double a[8];
	while(scanf("%lf", &a[0]) != EOF){
		double x1, x2, y1, y2;
		for(int i = 1;i < 8;i++)scanf("%lf", &a[i]);
		x1 = a[2] - a[0];y1 = a[3] - a[1];
		x2 = a[6] - a[4];y2 = a[7] - a[5];
		if(y1 * y2 == -1 * x1 * x2)printf("YES\n");
		else printf("NO\n");
	}
	return 0;
}