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



while a > 0 or c > 0:

    c -= b

    if c <= 0:

        print("Yes")

        exit()

    a -= d

    if a <= 0:

        print("No")

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



attack_t = c // b

if c % b != 0:

    attack_t += 1



attack_a = a // d

if a % d != 0:

    attack_a += 1



if attack_a >= attack_t:

    print("Yes")

else:

    print("No")

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

a, b, c, d = list(map(int, input().split()))
attack_t = c // b
if c % b != 0:
    attack_t += 1
attack_a = a // d
if a % d != 0:
    attack_a += 1
if attack_a >= attack_t:
    print("Yes")
else:
    print("No")

-while a > 0 or c > 0: -    c -= b -    if c <= 0: -        print("Yes") -        exit() -    a -= d -    if a <= 0: -        print("No") -        exit() +attack_t = c // b +if c % b != 0: +    attack_t += 1 +attack_a = a // d +if a % d != 0: +    attack_a += 1 +if attack_a >= attack_t: +    print("Yes") +else: +    print("No")