#include<cstdio>
#include<cmath>
#include<algorithm>
#include<iostream>
#include<string>
#include <vector>
#include <map>
#include<cstdlib>


using namespace std;

void Solution()
{
    double xA, yA;
    double xB, yB;
    double xC, yC;
    double xD, yD;
    
    while(cin>>xA>>yA>>xB>>yB>>xC>>yC>>xD>>yD)
    {
        //algorithm
        double a, b, c, d;
        
        a = (yA-yB);
        b = (xA-xB);
        c = (yC-yD);
        d = (xC-xD);
        
        if(a*c + b*d == 0)
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
    }

}


int main()
{
    Solution();
    return 0;
}