#include<iostream>
using namespace std;
double xa,ya,xb,yb,xc,yc,xd,yd;

int main(){
    while(cin>>xa>>ya>>xb>>yb>>xc>>yc>>xd>>yd){
        !((xb-xa)*(xd-xc)+(yb-ya)*(yd-yc))?cout<<"YES"<<endl:cout<<"NO"<<endl;
    }
}