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: Wrong Answer)

function Main(input) {
  var inputs = input.split(' '),
    len = inputs.length
  var N, K
  // if (len > 2 || len === 0) {
  //   console.log('NO')
  //   return
  // }
  // for (var i = 0; i < len; i++) {
  //   if (/^\d+$/.test(inputs[i]) !== -1) {
  //     console.log('NO')
  //     return
  //   }
  // }
  // try {
  N = parseInt(inputs[0], 10)
  K = parseInt(inputs[1], 10)
  // } catch (e) {
  //   console.log('NO')
  //   return
  // }

  if (N < 1 && N > 100) {
    console.log('NO')
    return
  }
  if (K < 1 && K > 100) {
    console.log('NO')
    return
  }

  if (N > K) {
    console.log('YES')
    return
  }
  console.log('NO')
  return
}
Main(require('fs').readFileSync('/dev/stdin', 'utf8'))