int main()
{

    float line1;
    float line2;
    float x1,x2,x3,x4;
    float y1,y2,y3,y4;

    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4;

    line1 = (y2-y1)/(x2-x1);
    line2 = (y4-y3)/(x4-x3);

    if (line1 == line2)
        {
        cout << "YES" << endl;
        }
    else
        {
        cout << "NO" << endl;
        }



    return 0;
}