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


using namespace std;

void Solution()
{
    double x1, x2;
    double y1, y2;
    double x3, x4;
    double y3, y4;
    
    while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4)
    {
        double a = (x2 - x1) * (x4 - x3);
        double b = (y2 - y1) * (y4 - y3);
        
        if((float)a + (float)b == 0) // don't forget change to float
        {
            cout<<"YES"<<endl;
        }
        else
        {
            cout<<"NO"<<endl;
        }
        
    }
}

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