#include <iostream>

using namespace std;

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

### Prompt

In cpp, your task is to solve 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>

using namespace std;

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

```