import math


def solution(N, K):
    if (math.floor((N + 1) / 2) >= K):
        return "YES"
    else:
        return "NO"


n, k = [int(s) for s in input().split(' ')]
print(solution(n, k)) import math math def solution(N, K):
    if (math.floor((N + 1) / 2) >= K):
        return "YES"
    else:
        return "NO" solution if (math.floor((N + 1) / 2) >= K):
        return "YES"
    else:
        return "NO" math.floor((N + 1) / 2) >= K math.floor((N + 1) / 2) math.floor math floor (N + 1) / 2 N + 1 N 1 2 K return "YES" "YES" return "NO" "NO" N N K K int(s) for s in input().split(' ') for s in input().split(' ') s input().split(' ') ().split () input split ' ' for s in input().split(' ') int(s) int s n, k = [int(s) for s in input().split(' ')] n [int(s) for s in input().split(' ')] k print(solution(n, k)) print solution(n, k) solution n k k = [int(s) for s in input().split(' ')] [int(s) for s in input().split(' ')] k def solution(N, K):
    if (math.floor((N + 1) / 2) >= K):
        return "YES"
    else:
        return "NO" def solution(N, K):
    if (math.floor((N + 1) / 2) >= K):
        return "YES"
    else:
        return "NO" solution n, k = [int(s) for s in input().split(' ')] [int(s) for s in input().split(' ')] n
import math


def solution(N, K):
    if (math.floor((N + 1) / 2) >= K):
        return "YES"
    else:
        return "NO"


n, k = [int(s) for s in input().split(' ')]
print(solution(n, k))
