#include <bits/stdc++.h>
using namespace std;

int main() {
   int n,k;
   cin>>n>>k;
   if((n-1)/2>=k-1) cout<<"YES";
   else cout<<"NO";
return 0;
}

### 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 <bits/stdc++.h>
using namespace std;

int main() {
   int n,k;
   cin>>n>>k;
   if((n-1)/2>=k-1) cout<<"YES";
   else cout<<"NO";
return 0;
}

```