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 JavaScript (node.js v5.12) (judge verdict: Accepted)

'use strict'

const main = (INPUT) => {
  const N = Number(INPUT.split('\n')[0].split(' ')[0])
  const K = Number(INPUT.split('\n')[0].split(' ')[1])

  if ((N + 1) / 2 >= K) {
    console.log('YES')
  } else {
    console.log('NO')
  }
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'))