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 Go (1.6) (judge verdict: Wrong Answer)

package main

import(
	"bufio"
	"fmt"
	"os"
)

func main() {
	var n int
	var k int
	var num int
	sc := bufio.NewScanner(os.Stdin)
	sc.Scan()
	fmt.Sscanf(sc.Text(), "%d %d", &n, &k)

	if n%2 == 0{
		num = n/2
	} else {
		num = ((n+1)/2) + 1
	}


	if k <= num{
		fmt.Println("YES")
	} else {
		fmt.Println("NO")
	}
}