def ii():return int(input())
def iim():return map(int,input().split())
def iil():return list(map(int,input().split()))
def ism():return map(str,input().split())
def isl():return list(map(str,input().split()))

n,k =iim()
if n%2 == 0:
    if k <= n//2:
        print('YES')
    else:
        print('NO')
elif k <= (n-1)//2+1:
    print('YES')
else:
    print('NO') def ii():return int(input()) ii def iim():return map(int,input().split()) iim def iil():return list(map(int,input().split())) iil def ism():return map(str,input().split()) ism def isl():return list(map(str,input().split())) isl n,k =iim() n iim() iim k if n%2 == 0:
    if k <= n//2:
        print('YES')
    else:
        print('NO')
elif k <= (n-1)//2+1:
    print('YES')
else:
    print('NO') n%2 == 0 n%2 n 2 0 if k <= n//2:
        print('YES')
    else:
        print('NO') k <= n//2 k n//2 n 2 print('YES') print 'YES' print('NO') print 'NO' elif k <= (n-1)//2+1:
    print('YES') k <= (n-1)//2+1 k (n-1)//2+1 (n-1)//2 n-1 n 1 2 1 print('YES') print 'YES' print('NO') print 'NO' n,k =iim() iim() n k =iim() iim() k def ii():return int(input()) def ii():return int(input()) ii def iil():return list(map(int,input().split())) def iil():return list(map(int,input().split())) iil def iim():return map(int,input().split()) def iim():return map(int,input().split()) iim def ism():return map(str,input().split()) def ism():return map(str,input().split()) ism def isl():return list(map(str,input().split())) def isl():return list(map(str,input().split())) isl
def ii():return int(input())
def iim():return map(int,input().split())
def iil():return list(map(int,input().split()))
def ism():return map(str,input().split())
def isl():return list(map(str,input().split()))

n,k =iim()
if n%2 == 0:
    if k <= n//2:
        print('YES')
    else:
        print('NO')
elif k <= (n-1)//2+1:
    print('YES')
else:
    print('NO')