while True:

    try:

        xA,yA,xB,yB,xC,yC,xD,yD = list(map(float, input().split()))

        if abs((yB-yA)*(yD-yC) + (xB-xA)*(xD-xC)) < 1.e-12:

                print("YES")

        else:

            print("NO")

    except:

        break
while True:

    try:

        xA,yA,xB,yB,xC,yC,xD,yD = list(map(float, input().split()))

        if abs((yB-yA)*(yD-yC) + (xB-xA)*(xD-xC)) < 1.e-10:

                print("YES")

        else:

            print("NO")

    except:

        break
while True:
    try:
        xA, yA, xB, yB, xC, yC, xD, yD = list(map(float, input().split()))
        if abs((yB - yA) * (yD - yC) + (xB - xA) * (xD - xC)) < 1.0e-12:
            print("YES")
        else:
            print("NO")
    except:
        break

while True:
    try:
        xA, yA, xB, yB, xC, yC, xD, yD = list(map(float, input().split()))
        if abs((yB - yA) * (yD - yC) + (xB - xA) * (xD - xC)) < 1.0e-10:
            print("YES")
        else:
            print("NO")
    except:
        break

-        if abs((yB - yA) * (yD - yC) + (xB - xA) * (xD - xC)) < 1.0e-12: +        if abs((yB - yA) * (yD - yC) + (xB - xA) * (xD - xC)) < 1.0e-10: