#include<cstdio>
#include<algorithm>
#include<vector>
#include<string>
#include<iostream>
#include<queue>
#include<map>
#include<set>
#include<complex>
#include<stack>
#include<cmath>

using namespace std;

#define reps(i,f,n) for(int i=f;i<int(n);i++)
#define rep(i,n) reps(i,0,n)

int main(){
	double eps = 10e-7;
	double xA,yA,xB,yB,xC,yC,xD,yD;
	while(~scanf("%lf %lf %lf %lf %lf %lf %lf %lf",
		&xA,&yA,&xB,&yB,&xC,&yC,&xD,&yD)){
			if((xB-xA)*(xD-xC)+(yB-yA)*(yD-yC) == 0){
				cout << "YES" << endl;
			}else{
				cout << "NO" << endl;
			}
	}
}