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高桥和青木将使用他们的怪物进行一场战斗。

高桥的怪物的生命值和力量分别为AA和BB，青木的怪物分别为CC和DD。

两个怪物将轮流攻击，顺序是高桥、青木、高桥、青木。在这里，攻击会使对手的生命值降低与攻击者力量相等的值。怪物不断攻击，直到一个怪物的生命值达到或低于0。生命值首先达到或低于0的人会输，而另一个人会赢。

如果高桥获胜，请打印“Yes”；否则打印“No”。

Problem Statement

Takahashi and Aoki will have a battle using their monsters.
The health and strength of Takahashi's monster are

A

and

B

, respectively, and those of Aoki's monster are

C

and

D

, respectively.
The two monsters will take turns attacking, in the order Takahashi's, Aoki's, Takahashi's, Aoki's, ... Here, an attack decreases the opponent's health by the value equal to the attacker's strength. The monsters keep attacking until the health of one monster becomes

0

or below. The person with the monster whose health becomes

0

or below loses, and the other person wins.
If Takahashi will win, print Yes; if he will lose, print No.

Constraints

$\leq A,B,C,D \leq 100$
All values in input are integers.

Input

Input is given from Standard Input in the following format:

 $A$  $B$  $C$  $D$

Output

If Takahashi will win, print Yes; if he will lose, print No.

2188: abc164b - battle

Description

Problem Statement

Constraints

Input

Output

Sample Input Copy

Sample Output Copy

HINT

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