#include<iostream>
using namespace std;
int main(){
double xa,ya,xb,yb,xc,yc,xd,yd;
while(cin>>xa){
cin>>ya>>xb>>yb>>xc>>yc>>xd>>yd;
if((yb-ya)*(yd-yc)+(xb-xa)*(xd-xc)==0)cout<<"YES"<<endl;
else cout<<"NO"<<endl;
}
return 0;
}