#define	_USE_MATH_DEFINES
#include <iostream>
#include <algorithm>
#include <functional>
#include <vector>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cfloat>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <string>
#include <set>
using namespace std;
int main(){
	
	
	double x1,x2,x3,x4,y1,y2,y3,y4;
	
	while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4){
		double E=1e-10;
		if(abs((x2-x1)*(x4-x3)+(y2-y1)*(y4-y3))<E)
			cout<<"YES"<<endl;
		else
			cout<<"NO"<<endl;
	}
	return 0;

	
}