#include <stdio.h>
int main(void){
  int n,k;
  
  scanf("%d %d", &n, &k);

  if((n+1)/2 >= k){
    printf("YES");
  }else{
    printf("NO");
  }

}

### Prompt

Please provide a CPP coded solution to the problem described below:

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 <stdio.h>
int main(void){
  int n,k;
  
  scanf("%d %d", &n, &k);

  if((n+1)/2 >= k){
    printf("YES");
  }else{
    printf("NO");
  }

}

```