#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 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)!=EOF){
		
		if(fabs((xb-xa)*(xd-xc)+(yb-ya)*(yd-yc))<0.000000000001==0)puts("YES");
		else puts("NO");
	}
}