import bisect, collections, copy, heapq, itertools, math, string, sys
input = lambda: sys.stdin.readline().rstrip() 
sys.setrecursionlimit(10**7)
INF = float('inf')
def I(): return int(input())
def F(): return float(input())
def SS(): return input()
def LI(): return [int(x) for x in input().split()]
def LI_(): return [int(x)-1 for x in input().split()]
def LF(): return [float(x) for x in input().split()]
def LSS(): return input().split()

def resolve():
    N, K = LI()

    ans = 0
    for i in range(1, N + 1):
        tmp = 1 / N
        score = i
        while 1 <= score <= K - 1:
            score *= 2
            tmp *= 0.5
        ans += tmp

    print(ans)

if __name__ == '__main__':
    resolve() import bisect, collections, copy, heapq, itertools, math, string, sys bisect collections copy heapq itertools math string sys input = lambda: sys.stdin.readline().rstrip() input lambda: sys.stdin.readline().rstrip() sys.stdin.readline().rstrip() sys.stdin.readline().rstrip sys.stdin.readline() sys.stdin.readline sys.stdin sys stdin readline rstrip sys.setrecursionlimit(10**7) sys.setrecursionlimit sys setrecursionlimit 10**7 10 7 INF = float('inf') INF float('inf') float 'inf' def I(): return int(input()) I def F(): return float(input()) F def SS(): return input() SS int(x) for x in input().split() for x in input().split() x input().split() ().split () input split for x in input().split() int(x) int x def LI(): return [int(x) for x in input().split()] LI int(x)-1 for x in input().split() for x in input().split() x input().split() ().split () input split for x in input().split() int(x)-1 int(x) int x 1 def LI_(): return [int(x)-1 for x in input().split()] LI_ float(x) for x in input().split() for x in input().split() x input().split() ().split () input split for x in input().split() float(x) float x def LF(): return [float(x) for x in input().split()] LF def LSS(): return input().split() LSS def resolve():
    N, K = LI()

    ans = 0
    for i in range(1, N + 1):
        tmp = 1 / N
        score = i
        while 1 <= score <= K - 1:
            score *= 2
            tmp *= 0.5
        ans += tmp

    print(ans) resolve N, K = LI() N LI() LI K ans = 0 ans 0 for i in range(1, N + 1):
        tmp = 1 / N
        score = i
        while 1 <= score <= K - 1:
            score *= 2
            tmp *= 0.5
        ans += tmp

     i range(1, N + 1) range 1 N + 1 N 1 tmp = 1 / N tmp 1 / N 1 N score = i score i while 1 <= score <= K - 1:
            score *= 2
            tmp *= 0.5
         1 <= score <= K - 1 1 <= score 1 score K - 1 K 1 score *= 2 score 2 tmp *= 0.5 tmp 0.5 ans += tmp ans tmp print(ans) print ans if __name__ == '__main__':
    resolve() __name__ == '__main__' __name__ '__main__' resolve() resolve INF = float('inf') float('inf') INF def LI(): return [int(x) for x in input().split()] def LI(): return [int(x) for x in input().split()] LI def LI_(): return [int(x)-1 for x in input().split()] def LI_(): return [int(x)-1 for x in input().split()] LI_ def resolve():
    N, K = LI()

    ans = 0
    for i in range(1, N + 1):
        tmp = 1 / N
        score = i
        while 1 <= score <= K - 1:
            score *= 2
            tmp *= 0.5
        ans += tmp

    print(ans) def resolve():
    N, K = LI()

    ans = 0
    for i in range(1, N + 1):
        tmp = 1 / N
        score = i
        while 1 <= score <= K - 1:
            score *= 2
            tmp *= 0.5
        ans += tmp

    print(ans) resolve input = lambda: sys.stdin.readline().rstrip() lambda: sys.stdin.readline().rstrip() input def I(): return int(input()) def I(): return int(input()) I def F(): return float(input()) def F(): return float(input()) F def SS(): return input() def SS(): return input() SS def LF(): return [float(x) for x in input().split()] def LF(): return [float(x) for x in input().split()] LF def LSS(): return input().split() def LSS(): return input().split() LSS
import bisect, collections, copy, heapq, itertools, math, string, sys
input = lambda: sys.stdin.readline().rstrip() 
sys.setrecursionlimit(10**7)
INF = float('inf')
def I(): return int(input())
def F(): return float(input())
def SS(): return input()
def LI(): return [int(x) for x in input().split()]
def LI_(): return [int(x)-1 for x in input().split()]
def LF(): return [float(x) for x in input().split()]
def LSS(): return input().split()

def resolve():
    N, K = LI()

    ans = 0
    for i in range(1, N + 1):
        tmp = 1 / N
        score = i
        while 1 <= score <= K - 1:
            score *= 2
            tmp *= 0.5
        ans += tmp

    print(ans)

if __name__ == '__main__':
    resolve()
