#include <iostream>
using namespace std;
 
int main()
{
    while(true){
        double xA, yA, xB, yB, xC, yC, xD, yD;
        cin >> xA;
        if(cin.eof())
            break;
        cin >> yA >> xB >> yB >> xC >> yC >> xD >> yD;
 
        double xAB = xB-xA;
        double yAB = yB-yA;
        double xCD = xD-xC;
        double yCD = yD-yC;
 
        if(xAB*xCD+yAB*yCD==0.0)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
 
    return 0;
}