a,b,c,d = list(map(int, input().split()))



turn_taka = True

while True:

    if turn_taka:

        c -= b

    else:

        a -= d



    if a <= 0:

        print('No')

        break

    if c <= 0:

        print('Yes')

        break



    turn_taka = not turn_taka

a,b,c,d = list(map(int, input().split()))



while True:

    c -= b

    a -= d



    if c <= 0:

        print('Yes')

        break

    if a <= 0:

        print('No')

        break

a, b, c, d = list(map(int, input().split()))
turn_taka = True
while True:
    if turn_taka:
        c -= b
    else:
        a -= d
    if a <= 0:
        print("No")
        break
    if c <= 0:
        print("Yes")
        break
    turn_taka = not turn_taka

a, b, c, d = list(map(int, input().split()))
while True:
    c -= b
    a -= d
    if c <= 0:
        print("Yes")
        break
    if a <= 0:
        print("No")
        break

-turn_taka = True -    if turn_taka: -        c -= b -    else: -        a -= d +    c -= b +    a -= d +    if c <= 0: +        print("Yes") +        break -    if c <= 0: -        print("Yes") -        break -    turn_taka = not turn_taka