
Score : 100 points
Problem StatementDetermine 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.
InputInput is given from Standard Input in the following format:
N K
OutputIf we can choose K integers as above, print YES; otherwise, print NO.
Sample Input 13 2
Sample Output 1YES
We can choose 1 and 3.
Sample Input 25 5
Sample Output 2NO
Sample Input 331 10
Sample Output 3YES
Sample Input 410 90
Sample Output 4NO
