#include <iostream>

int main(){
    int n,k;
    std::cin>>n>>k;
    int x =(n%2? n/2+1:n/2);
    std::cout<<(x<k?"NO":"YES");
}
### Prompt

Your task is to create 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 <iostream>

int main(){
    int n,k;
    std::cin>>n>>k;
    int x =(n%2? n/2+1:n/2);
    std::cout<<(x<k?"NO":"YES");
}
```