#include <bits/stdc++.h>
using namespace std;
int main(){
  int N,K;cin>>N>>K;
  if((N+1)/2<K)cout<<"NO"<<endl;
  else cout<<"YES"<<endl;
}
### 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 <bits/stdc++.h>
using namespace std;
int main(){
  int N,K;cin>>N>>K;
  if((N+1)/2<K)cout<<"NO"<<endl;
  else cout<<"YES"<<endl;
}
```