#include <string>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <vector>
#include <queue>
#include <set>
#include <utility>
#include <algorithm>
#include <numeric>
#include <iostream>
#include <iterator>
#include <sstream>

using namespace std;

double dot(double x1,double y1,double x2,double y2)
{
	return x1 * x2 + y1 * y2;
}

int main()
{
	double x1,x2,x3,x4,y1,y2,y3,y4;
	while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4){
		double s = dot(x2-x1,y2-y1,x4-x3,y4-y3);
		if(abs(s) <= 1e-10) puts("YES");
		else puts("NO");
	}
	return 0;
}