#include <iostream>
#include <stdio.h>
using namespace std;
 
int main() {
    double ax, ay;
    double bx, by;
    double cx, cy;
    double dx, dy;
    
    double ex, ey;
    double fx, fy; 
    
    while(cin>>ax>>ay>>bx>>by>>cx>>cy>>dx>>dy)
    {
        ex = ax - bx; 
        ey = ay - by;
        fx = cx - dx; 
        fy = cy - dy;
        
        if (ex * fx + ey * fy == 0) 
            cout<<"YES"<<endl; 
        else 
            cout<<"NO"<<endl;
    }
    return 0;
}