#21 C - Dice and Coin
import math
N,K = map(int,input().split())

ans = 0
for i in range(1,N+1):
    if K//i != 0:
        a = math.log2(K/i)
        if a.is_integer():
            x = int(a)
        else:
            x = int(a) + 1
        ans += (1/N)*(1/2)**x
    else:
        ans += (1/N)
print(ans) import math math N,K = map(int,input().split()) N map(int,input().split()) map int input().split() ().split () input split K ans = 0 ans 0 for i in range(1,N+1):
    if K//i != 0:
        a = math.log2(K/i)
        if a.is_integer():
            x = int(a)
        else:
            x = int(a) + 1
        ans += (1/N)*(1/2)**x
    else:
        ans += (1/N) i range(1,N+1) range 1 N+1 N 1 if K//i != 0:
        a = math.log2(K/i)
        if a.is_integer():
            x = int(a)
        else:
            x = int(a) + 1
        ans += (1/N)*(1/2)**x
    else:
        ans += (1/N) K//i != 0 K//i K i 0 a = math.log2(K/i) a math.log2(K/i) math.log2 math log2 K/i K i if a.is_integer():
            x = int(a)
        else:
            x = int(a) + 1
         a.is_integer() a.is_integer a is_integer x = int(a) x int(a) int a x = int(a) + 1 x int(a) + 1 int(a) int a 1 ans += (1/N)*(1/2)**x ans (1/N)*(1/2)**x 1/N 1 N (1/2)**x 1/2 1 2 x ans += (1/N) ans 1/N 1 N print(ans) print ans ans += (1/N)*(1/2)**x (1/N)*(1/2)**x ans ans += (1/N) 1/N ans K = map(int,input().split()) map(int,input().split()) K x = int(a) int(a) x a = math.log2(K/i) math.log2(K/i) a ans = 0 0 ans N,K = map(int,input().split()) map(int,input().split()) N x = int(a) + 1 int(a) + 1 x
#21 C - Dice and Coin
import math
N,K = map(int,input().split())

ans = 0
for i in range(1,N+1):
    if K//i != 0:
        a = math.log2(K/i)
        if a.is_integer():
            x = int(a)
        else:
            x = int(a) + 1
        ans += (1/N)*(1/2)**x
    else:
        ans += (1/N)
print(ans)