# 有理数型による比較解法

import sys
from fractions import Fraction

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

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

LHS = Fraction(a, b)
RHS = Fraction(c, d)

print('Yes' if LHS < RHS else 'No')