#!/usr/bin/env python
# -*- coding: utf-8 -*-

# みんなのプロコン 2019：A - Anti-Adjacency


def main():
    N, K = [int(i) for i in raw_input().strip().split(' ')]

    if N >= K*2 - 1:
        print 'YES'
    else:
        print 'NO'


if __name__ == '__main__':
    main() def main():
    N, K = [int(i) for i in raw_input().strip().split(' ')]

    if N >= K*2 - 1:
        print 'YES'
    else:
        print 'NO' main int(i) for i in raw_input().strip().split(' ') for i in raw_input().strip().split(' ') i raw_input().strip().split(' ') ().strip().split ().strip() ().strip () raw_input strip split ' ' for i in raw_input().strip().split(' ') int(i) int i N, K = [int(i) for i in raw_input().strip().split(' ')] N [int(i) for i in raw_input().strip().split(' ')] K if N >= K*2 - 1:
        print 'YES'
    else:
        print 'NO' N >= K*2 - 1 N K*2 - 1 K*2 K 2 1 print print if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    N, K = [int(i) for i in raw_input().strip().split(' ')]

    if N >= K*2 - 1:
        print 'YES'
    else:
        print 'NO' def main():
    N, K = [int(i) for i in raw_input().strip().split(' ')]

    if N >= K*2 - 1:
        print 'YES'
    else:
        print 'NO' main
#!/usr/bin/env python
# -*- coding: utf-8 -*-

# みんなのプロコン 2019：A - Anti-Adjacency


def main():
    N, K = [int(i) for i in raw_input().strip().split(' ')]

    if N >= K*2 - 1:
        print 'YES'
    else:
        print 'NO'


if __name__ == '__main__':
    main()
