Problem:
Score : 100 points

Problem Statement

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.

Sample Input 1

3 2

Sample Output 1

YES

We can choose 1 and 3.

Sample Input 2

5 5

Sample Output 2

NO

Sample Input 3

31 10

Sample Output 3

YES

Sample Input 4

10 90

Sample Output 4

NO

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

package proCon_minnano2019_20190209;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
    	int n,k;
    	n = in.nextInt();
    	k = in.nextInt();
    	String ans = "NO";
    	if (k <= (n/2 + n%2)) ans = "YES";
    	
    	System.out.println(ans);
    }
}