#include<bits/stdc++.h>

using namespace std;


int main(){
int n,k;
cin >> n >> k;
if(n+1>=2*k){cout << "YES";}
else cout << "NO";



}

### Prompt

Develop a solution in CPP 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<bits/stdc++.h>

using namespace std;


int main(){
int n,k;
cin >> n >> k;
if(n+1>=2*k){cout << "YES";}
else cout << "NO";



}

```