#!usr/bin/env python3
from collections import defaultdict
from collections import deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
import itertools
sys.setrecursionlimit(10**5)
stdin = sys.stdin
bisect_left = bisect.bisect_left
bisect_right = bisect.bisect_right
def LI(): return list(map(int, stdin.readline().split()))
def LF(): return list(map(float, stdin.readline().split()))
def LI_(): return list(map(lambda x: int(x)-1, stdin.readline().split()))
def II(): return int(stdin.readline())
def IF(): return float(stdin.readline())
def LS(): return list(map(list, stdin.readline().split()))
def S(): return list(stdin.readline().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')

#A
def A():
    n, k = LI()
    s = S()
    s[k-1] = s[k-1].lower()
    print("".join(s))

    return

#B
def B():
    s = S()
    a = int("".join(s[:2]))
    b = int("".join(s[2:]))
    if 0 < a <= 12:
        if 0 < b <= 12:
            print("AMBIGUOUS")
        else:
            print("MMYY")
    elif a == 0:
        if 0 < b <= 12:
            print("YYMM")
        else:
            print("NA")
    else:
        if 0 < b <= 12:
            print("YYMM")
        else:
            print("NA")
    return

#C
def C():
    n, k = LI()
    ans = 0
    if k == 1:
        print(1)
        return
    nibuiti = [None for i in range(int(math.log2(k) + 1))]
    for num, i in enumerate(nibuiti):
        if num == 0:
            nibuiti[num] = 1 / 2
            continue
        nibuiti[num] = nibuiti[num-1]/2
        
    for i in range(1, n + 1):
        if i >= k:
            ans += 1
            continue
        b = nibuiti[int(math.log2((k - 1) // i))]
        ans += b
    print(ans/n)
    return

#D
def D():
    return

#E
def E():
    return

#F
def F():
    return

#G
def G():
    return

#H
def H():
    return

#Solve
if __name__ == '__main__':
    C()


### FIXED CODE ###

#!usr/bin/env python3
from collections import defaultdict
from collections import deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
import itertools
sys.setrecursionlimit(10**5)
stdin = sys.stdin
bisect_left = bisect.bisect_left
bisect_right = bisect.bisect_right
def LI(): return list(map(int, stdin.readline().split()))
def LF(): return list(map(float, stdin.readline().split()))
def LI_(): return list(map(lambda x: int(x)-1, stdin.readline().split()))
def II(): return int(stdin.readline())
def IF(): return float(stdin.readline())
def LS(): return list(map(list, stdin.readline().split()))
def S(): return list(stdin.readline().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')

#A
def A():
    n, k = LI()
    s = S()
    s[k-1] = s[k-1].lower()
    print("".join(s))

    return

#B
def B():
    s = S()
    a = int("".join(s[:2]))
    b = int("".join(s[2:]))
    if 0 < a <= 12:
        if 0 < b <= 12:
            print("AMBIGUOUS")
        else:
            print("MMYY")
    elif a == 0:
        if 0 < b <= 12:
            print("YYMM")
        else:
            print("NA")
    else:
        if 0 < b <= 12:
            print("YYMM")
        else:
            print("NA")
    return

#C
def C():
    n, k = LI()
    ans = 0
    if k == 1:
        print(1)
        return
    nibuiti = [None for i in range(int(math.log2(k) + 1))]
    for num in range(int(math.log2(k) + 1)):
        if num == 0:
            nibuiti[num] = 1 / 2
            continue
        nibuiti[num] = nibuiti[num-1]/2
        
    for i in range(1, n + 1):
        if i >= k:
            ans += 1
            continue
        b = nibuiti[int(math.log2((k - 1) // i))]
        ans += b
    print(ans/n)
    return

#D
def D():
    return

#E
def E():
    return

#F
def F():
    return

#G
def G():
    return

#H
def H():
    return

#Solve
if __name__ == '__main__':
    C()