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()

import math

A, B, C, D = list(map(int, input().split()))

print(("Yes" if math.ceil(C / B) <= math.ceil(A / D) else "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()

import math

A, B, C, D = list(map(int, input().split()))
print(("Yes" if math.ceil(C / B) <= math.ceil(A / D) else "No"))

+import math + -while A > 0 or C > 0: -    C -= B -    if C <= 0: -        print("Yes") -        exit() -    A -= D -    if A <= 0: -        print("No") -        exit() +print(("Yes" if math.ceil(C / B) <= math.ceil(A / D) else "No"))