#include<stdio.h>
#include<cstdio>
#include<iostream>
double abs(double a){return a<0?-a:a;}
int main(){
    double xa,xb,xc,xd,ya,yb,yc,yd;
    while(~scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&xa,&ya,&xb,&yb,&xc,&yc,&xd,&yd)){
        double t=(xa-xb)*(xc-xd)+(ya-yb)*(yc-yd);
        if(abs(t)<0.00001)printf("YES\n");
        else printf("NO\n");
    }
}
