Score : $100$ points

Problem Statement

Determine if we can choose $K$ different integers between $1$ and $N$ (inclusive) so that no two of them differ by $1$.

Constraints

• $1\leq N,K\leq 100$
• $N$ and $K$ are integers.

Input

Input is given from Standard Input in the following format:

$N$ $K$

Output

If we can choose $K$ integers as above, print YES; otherwise, print NO.

3 2

YES

We can choose $1$ and $3$.

5 5

NO

31 10

YES

10 90

NO