output_description: If we can choose K integers as above, print `YES`; otherwise, print `NO`.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
attempt: # import bisect
  # import heapq
  # import math
  # import random
  # from fractions import gcd
  # from collections import Counter, defaultdict, deque
  # from decimal import Decimal
  # from functools import lru_cache, reduce
  # from itertools import combinations, combinations_with_replacement, product, permutations
  # from operator import add, mul, sub, itemgetter
  # import numpy as np
  
  import sys
  
  sys.setrecursionlimit(10000)
  
  
  def read_int(read=None):
      if read == None:
          read = sys.stdin.readline().strip()
      return int(read)
  
  
  def read_int_n(read=None):
      if read == None:
          read = sys.stdin.readline().strip()
      return [int(x) for x in read.split()]
  
  
  def read_float(read=None):
      if read == None:
          read = sys.stdin.readline().strip()
      return float(read)
  
  
  def read_float_n(read=None):
      if read == None:
          read = sys.stdin.readline().strip()
      return [float(x) for x in read.split()]
  
  
  def read_str(read=None):
      if read == None:
          read = sys.stdin.readline().strip()
      return str(read)
  
  
  def read_str_n(read=None):
      if read == None:
          read = sys.stdin.readline().strip()
      return [str(x) for x in read.split()]
  
  
  def error_print(*args):
      print(*args, file=sys.stderr)
  
  
  def mt(f):
      import time
  
      def wrap(*args, **kwargs):
          s = time.time()
          ret = f(*args, **kwargs)
          e = time.time()
          error_print(e - s, "sec")
          return ret
  
      return wrap
  
  
  @mt
  def slv(N, K):
      if N + 1 >= 2 * K:
          ans = "YES"
      else:
          ans = "NO"
      return ans
  
  
  def main():
      t = """
  	""".splitlines()
      N, K = read_int_n()
      print(slv(N, K))
  
  
  if __name__ == "__main__":
      main()
  
problem_description: Statement
  
  Determine if we can choose K different integers between 1 and N (inclusive) so
  that no two of them differ by 1.
samples: [{"input": "3 2", "output": "YES\n    \n\nWe can choose 1 and 3.\n\n* * *"}, {"input": "5 5", "output": "NO\n    \n\n* * *"}, {"input": "31 10", "output": "YES\n    \n\n* * *"}, {"input": "10 90", "output": "NO"}]