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

while A > 0:

    C -= B

    if C <= 0:

        print('Yes')

        break

    A -= D

    if A <= 0:

        print('No')

        break
import math

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

X = math.ceil(A / D)

Y = math.ceil(C / B)

if Y > X:

    print('No')

else:

    print('Yes')
[A, B, C, D] = list(map(int, input().split()))
while A > 0:
    C -= B
    if C <= 0:
        print("Yes")
        break
    A -= D
    if A <= 0:
        print("No")
        break

import math

[A, B, C, D] = list(map(int, input().split()))
X = math.ceil(A / D)
Y = math.ceil(C / B)
if Y > X:
    print("No")
else:
    print("Yes")

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