# -*- coding: utf-8 -*-
"""
A - Anti-Adjacency
https://atcoder.jp/contests/yahoo-procon2019-qual/tasks/yahoo_procon2019_qual_a

"""
import sys


def solve(N, K):
    if (N+1) //2 >= K:
        return 'YES'
    return 'NO'


def main(args):
    N, K = map(int, input().split())
    ans = solve(N, K)
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:]) """
A - Anti-Adjacency
https://atcoder.jp/contests/yahoo-procon2019-qual/tasks/yahoo_procon2019_qual_a

""" import sys sys def solve(N, K):
    if (N+1) //2 >= K:
        return 'YES'
    return 'NO' solve if (N+1) //2 >= K:
        return 'YES'
     (N+1) //2 >= K (N+1) //2 N+1 N 1 2 K return 'YES' 'YES' return 'NO' 'NO' N N K K def main(args):
    N, K = map(int, input().split())
    ans = solve(N, K)
    print(ans) main N, K = map(int, input().split()) N map(int, input().split()) map int input().split() ().split () input split K ans = solve(N, K) ans solve(N, K) solve N K print(ans) print ans args args if __name__ == '__main__':
    main(sys.argv[1:]) __name__ == '__main__' __name__ '__main__' main(sys.argv[1:]) main sys.argv[1:] sys.argv sys argv 1: 1 def main(args):
    N, K = map(int, input().split())
    ans = solve(N, K)
    print(ans) def main(args):
    N, K = map(int, input().split())
    ans = solve(N, K)
    print(ans) main def solve(N, K):
    if (N+1) //2 >= K:
        return 'YES'
    return 'NO' def solve(N, K):
    if (N+1) //2 >= K:
        return 'YES'
    return 'NO' solve
# -*- coding: utf-8 -*-
"""
A - Anti-Adjacency
https://atcoder.jp/contests/yahoo-procon2019-qual/tasks/yahoo_procon2019_qual_a

"""
import sys


def solve(N, K):
    if (N+1) //2 >= K:
        return 'YES'
    return 'NO'


def main(args):
    N, K = map(int, input().split())
    ans = solve(N, K)
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])
