#include <iostream>

using namespace std;

int main()
{
    double xA, yA, xB, yB, xC, yC, xD, yD;

    while(cin >> xA >> yA >> xB >> yB >> xC >> yC >> xD >> yD) {
        if (-0.0000000001 < (yA-yB) * (yC-yD) + (xC-xD) * (xA-xB) &&
                (yA-yB) * (yC-yD) + (xC-xD) * (xA-xB) < 0.0000000001) {
            cout << "YES" << endl;
        } else {
            cout << "NO" << endl;
        }
    }

    return 0;
}