#include <cstdio>

int main() {
	int N,K;
	scanf("%d%d",&N,&K);
	if(N>=K*2-1) {
		printf("YES\n");
	} else {
		printf("NO\n");
	}
	return 0;
}

### Prompt

Generate a cpp solution to the following problem:

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`.

Examples

Input

3 2


Output

YES


Input

5 5


Output

NO


Input

31 10


Output

YES


Input

10 90


Output

NO

### Response

```cpp
#include <cstdio>

int main() {
	int N,K;
	scanf("%d%d",&N,&K);
	if(N>=K*2-1) {
		printf("YES\n");
	} else {
		printf("NO\n");
	}
	return 0;
}

```