#include <iostream>
#include <cfloat>
using namespace std;

const double eps=1e-10;

int main(void){
    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)<DBL_EPSILON){
            cout<<"YES"<<endl;
        }else{
            cout<<"NO"<<endl;
        }
    }

    return 0;
}