'''input
31 10
'''
import time
import math
n, k = map(int, input().strip().split())
d = (n + 1) / 2
if k <= d:
	print("YES")
else:
	print("NO") '''input
31 10
''' import time time import math math n, k = map(int, input().strip().split()) n map(int, input().strip().split()) map int input().strip().split() ().strip().split ().strip() ().strip () input strip split k d = (n + 1) / 2 d (n + 1) / 2 n + 1 n 1 2 if k <= d:
	print("YES")
else:
	print("NO") k <= d k d print("YES") print "YES" print("NO") print "NO" d = (n + 1) / 2 (n + 1) / 2 d n, k = map(int, input().strip().split()) map(int, input().strip().split()) n k = map(int, input().strip().split()) map(int, input().strip().split()) k
'''input
31 10
'''
import time
import math
n, k = map(int, input().strip().split())
d = (n + 1) / 2
if k <= d:
	print("YES")
else:
	print("NO")