import sys

input_methods=['clipboard','file','key']
using_method=0
input_method=input_methods[using_method]

tin=lambda : map(int, input().split())
lin=lambda : list(tin())
mod=1000000007

#+++++

def main():
	#a = int(input())
	#b , c = tin()
	#s = input()
	b, c= tin()
	return 'YES' if (b + 1) // 2 >= c else 'NO'
	
	
	
#+++++
isTest=False

def pa(v):
	if isTest:
		print(v)
		
def input_clipboard():
	import clipboard
	input_text=clipboard.get()
	input_l=input_text.splitlines()
	for l in input_l:
		yield l

if __name__ == "__main__":
	if sys.platform =='ios':
		if input_method==input_methods[0]:
			ic=input_clipboard()
			input = lambda : ic.__next__()
		elif input_method==input_methods[1]:
			sys.stdin=open('inputFile.txt')
		else:
			pass
		isTest=True
	else:
		pass
		#input = sys.stdin.readline
			
	ret = main()
	if ret is not None:
		print(ret) import sys sys input_methods=['clipboard','file','key'] input_methods ['clipboard','file','key'] 'clipboard' 'file' 'key' using_method=0 using_method 0 input_method=input_methods[using_method] input_method input_methods[using_method] input_methods using_method tin=lambda : map(int, input().split()) tin lambda : map(int, input().split()) map(int, input().split()) map int input().split() ().split () input split lin=lambda : list(tin()) lin lambda : list(tin()) list(tin()) list tin() tin mod=1000000007 mod 1000000007 def main():
	#a = int(input())
	#b , c = tin()
	#s = input()
	b, c= tin()
	return 'YES' if (b + 1) // 2 >= c else 'NO'
	
	
	
#+++++ main b, c= tin() b tin() tin c return 'YES' if (b + 1) // 2 >= c else 'NO' 'YES' if (b + 1) // 2 >= c else 'NO' (b + 1) // 2 >= c (b + 1) // 2 b + 1 b 1 2 c 'YES' 'NO' isTest=False isTest False def pa(v):
	if isTest:
		print(v)
		 pa if isTest:
		print(v)
		 isTest print(v) print v v v def input_clipboard():
	import clipboard
	input_text=clipboard.get()
	input_l=input_text.splitlines()
	for l in input_l:
		yield l input_clipboard import clipboard clipboard input_text=clipboard.get() input_text clipboard.get() clipboard.get clipboard get input_l=input_text.splitlines() input_l input_text.splitlines() input_text.splitlines input_text splitlines for l in input_l:
		yield l l input_l yield l l if __name__ == "__main__":
	if sys.platform =='ios':
		if input_method==input_methods[0]:
			ic=input_clipboard()
			input = lambda : ic.__next__()
		elif input_method==input_methods[1]:
			sys.stdin=open('inputFile.txt')
		else:
			pass
		isTest=True
	else:
		pass
		#input = sys.stdin.readline
			
	ret = main()
	if ret is not None:
		print(ret) __name__ == "__main__" __name__ "__main__" if sys.platform =='ios':
		if input_method==input_methods[0]:
			ic=input_clipboard()
			input = lambda : ic.__next__()
		elif input_method==input_methods[1]:
			sys.stdin=open('inputFile.txt')
		else:
			pass
		isTest=True
	else:
		pass
		#input = sys.stdin.readline
			
	 sys.platform =='ios' sys.platform sys platform 'ios' if input_method==input_methods[0]:
			ic=input_clipboard()
			input = lambda : ic.__next__()
		elif input_method==input_methods[1]:
			sys.stdin=open('inputFile.txt')
		else:
			pass
		 input_method==input_methods[0] input_method input_methods[0] input_methods 0 ic=input_clipboard() ic input_clipboard() input_clipboard input = lambda : ic.__next__() input lambda : ic.__next__() ic.__next__() ic.__next__ ic __next__ elif input_method==input_methods[1]:
			sys.stdin=open('inputFile.txt')
		 input_method==input_methods[1] input_method input_methods[1] input_methods 1 sys.stdin=open('inputFile.txt') sys.stdin sys stdin open('inputFile.txt') open 'inputFile.txt' isTest=True isTest True ret = main() ret main() main if ret is not None:
		print(ret) ret is not None ret None print(ret) print ret isTest=False False isTest ic=input_clipboard() input_clipboard() ic mod=1000000007 1000000007 mod tin=lambda : map(int, input().split()) lambda : map(int, input().split()) tin def pa(v):
	if isTest:
		print(v)
		 def pa(v):
	if isTest:
		print(v)
		 pa using_method=0 0 using_method input_method=input_methods[using_method] input_methods[using_method] input_method isTest=True True isTest lin=lambda : list(tin()) lambda : list(tin()) lin def main():
	#a = int(input())
	#b , c = tin()
	#s = input()
	b, c= tin()
	return 'YES' if (b + 1) // 2 >= c else 'NO'
	
	
	
#+++++ def main():
	#a = int(input())
	#b , c = tin()
	#s = input()
	b, c= tin()
	return 'YES' if (b + 1) // 2 >= c else 'NO'
	
	
	
#+++++ main ret = main() main() ret input = lambda : ic.__next__() lambda : ic.__next__() input input_methods=['clipboard','file','key'] ['clipboard','file','key'] input_methods def input_clipboard():
	import clipboard
	input_text=clipboard.get()
	input_l=input_text.splitlines()
	for l in input_l:
		yield l def input_clipboard():
	import clipboard
	input_text=clipboard.get()
	input_l=input_text.splitlines()
	for l in input_l:
		yield l input_clipboard
import sys

input_methods=['clipboard','file','key']
using_method=0
input_method=input_methods[using_method]

tin=lambda : map(int, input().split())
lin=lambda : list(tin())
mod=1000000007

#+++++

def main():
	#a = int(input())
	#b , c = tin()
	#s = input()
	b, c= tin()
	return 'YES' if (b + 1) // 2 >= c else 'NO'
	
	
	
#+++++
isTest=False

def pa(v):
	if isTest:
		print(v)
		
def input_clipboard():
	import clipboard
	input_text=clipboard.get()
	input_l=input_text.splitlines()
	for l in input_l:
		yield l

if __name__ == "__main__":
	if sys.platform =='ios':
		if input_method==input_methods[0]:
			ic=input_clipboard()
			input = lambda : ic.__next__()
		elif input_method==input_methods[1]:
			sys.stdin=open('inputFile.txt')
		else:
			pass
		isTest=True
	else:
		pass
		#input = sys.stdin.readline
			
	ret = main()
	if ret is not None:
		print(ret)