import sys



readline = sys.stdin.readline

MOD = 10 ** 9 + 7

INF = float('INF')

sys.setrecursionlimit(10 ** 5)





def main():

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



    while True:

        c -= b

        if c <= 0:

            print("Yes")

            break



        a -= d

        if a <= 0:

            print("No")

            break





if __name__ == '__main__':

    main()

tkhp, tkat, aohp, aoat = list(map(int, input().split()))



while True:

    aohp -= tkat

    if aohp <= 0:

        print("Yes")

        break



    tkhp -= aoat

    if tkhp <= 0:

        print("No")

        break
import sys

readline = sys.stdin.readline
MOD = 10**9 + 7
INF = float("INF")
sys.setrecursionlimit(10**5)


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


if __name__ == "__main__":
    main()

tkhp, tkat, aohp, aoat = list(map(int, input().split()))
while True:
    aohp -= tkat
    if aohp <= 0:
        print("Yes")
        break
    tkhp -= aoat
    if tkhp <= 0:
        print("No")
        break

-import sys - -readline = sys.stdin.readline -MOD = 10**9 + 7 -INF = float("INF") -sys.setrecursionlimit(10**5) - - -def main(): -    a, b, c, d = list(map(int, readline().split())) -    while True: -        c -= b -        if c <= 0: -            print("Yes") -            break -        a -= d -        if a <= 0: -            print("No") -            break - - -if __name__ == "__main__": -    main() +tkhp, tkat, aohp, aoat = list(map(int, input().split())) +while True: +    aohp -= tkat +    if aohp <= 0: +        print("Yes") +        break +    tkhp -= aoat +    if tkhp <= 0: +        print("No") +        break