'''
Created on 2020/08/20

@author: harurun
'''
def main():
  import sys
  pin=sys.stdin.readline
  pout=sys.stdout.write
  perr=sys.stderr.write
  
  N,K=map(int,pin().split())
  t=0
  if N%2==0:
    t=N//2
  else:
    t=N//2+1
  if t>=K:
    print("YES")
    return 
  print("NO")
  return 

main() '''
Created on 2020/08/20

@author: harurun
''' def main():
  import sys
  pin=sys.stdin.readline
  pout=sys.stdout.write
  perr=sys.stderr.write
  
  N,K=map(int,pin().split())
  t=0
  if N%2==0:
    t=N//2
  else:
    t=N//2+1
  if t>=K:
    print("YES")
    return 
  print("NO")
  return  main import sys sys pin=sys.stdin.readline pin sys.stdin.readline sys.stdin sys stdin readline pout=sys.stdout.write pout sys.stdout.write sys.stdout sys stdout write perr=sys.stderr.write perr sys.stderr.write sys.stderr sys stderr write N,K=map(int,pin().split()) N map(int,pin().split()) map int pin().split() ().split () pin split K t=0 t 0 if N%2==0:
    t=N//2
  else:
    t=N//2+1
   N%2==0 N%2 N 2 0 t=N//2 t N//2 N 2 t=N//2+1 t N//2+1 N//2 N 2 1 if t>=K:
    print("YES")
    return 
   t>=K t K print("YES") print "YES" return print("NO") print "NO" return main() main def main():
  import sys
  pin=sys.stdin.readline
  pout=sys.stdout.write
  perr=sys.stderr.write
  
  N,K=map(int,pin().split())
  t=0
  if N%2==0:
    t=N//2
  else:
    t=N//2+1
  if t>=K:
    print("YES")
    return 
  print("NO")
  return  def main():
  import sys
  pin=sys.stdin.readline
  pout=sys.stdout.write
  perr=sys.stderr.write
  
  N,K=map(int,pin().split())
  t=0
  if N%2==0:
    t=N//2
  else:
    t=N//2+1
  if t>=K:
    print("YES")
    return 
  print("NO")
  return  main
'''
Created on 2020/08/20

@author: harurun
'''
def main():
  import sys
  pin=sys.stdin.readline
  pout=sys.stdout.write
  perr=sys.stderr.write
  
  N,K=map(int,pin().split())
  t=0
  if N%2==0:
    t=N//2
  else:
    t=N//2+1
  if t>=K:
    print("YES")
    return 
  print("NO")
  return 

main()