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 tmp = input.split(/\n/).map(str=>{return parseInt(str)});
    console.log((tmp[0] + 1) / tmp[1] >= 2 ? 'YES' : 'NO');
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));