#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 = xA - xB;
        double b = xC - xD;
        double c = yA - yB;
        double d = yC - yD;
        
        if (a * b + c * d == 0)
        {
            cout<<"YES"<<endl;
        }
        else
        {
            cout<<"NO"<<endl;
        }
    }
    return;
}


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