#include <iostream>

using namespace std;
 
int n;
double xa,ya,xb,yb,xc,yc,xd,yd;
 
int main(void){
    while(cin>>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;
    }
    return 0;
}