#include<iostream>
#include<iomanip>
#include<cmath>
using namespace std;

int main()
{
    double xa, ya, xb, yb, xc, yc, xd, yd;

    while( cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd )
    {
        xa *= 100000; ya *= 100000; xb *= 100000; yb *= 100000;
        xc *= 100000; yc *= 100000; xd *= 100000; yd *= 100000;
        long long lxa = (long long)xa; long long lya = (long long)ya; long long lxb = (long long)xb; long long lyb = (long long)yb;
        long long lxc = (long long)xc; long long lyc = (long long)yc; long long lxd = (long long)xd; long long lyd = (long long)yd;

        //cout <<  lxa << " " << lya << " " << lxb << " " << lyb << " " << lxc << " " << lyc << " " << lxd << " " << lyd << " " << endl;
        long long xab = lxb - lxa, yab = lyb - lya;
        long long xcd = lxd - lxc, ycd = lyd - lyc;

        long long inner_product = xab * xcd + yab * ycd;
        //long long inner_product = (xb*xd+xa*xc+yb*yd+ya*yc) - (xb*xc+xa*xd+yb*yc+ya*yd);

        //cout << inner_product << endl;

        if( inner_product == 0 )
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
    return 0;
}
