import math

X, K = map(int, input().split())

if X == 1:
    ans = 1.0 - 1.0 / (2 ** (K + 1))
    print("{0:.9f}".format(ans))
elif X == 2:
    if K == 1:
        print(0.5)
    else:
        if K >= 40:
            print(0.0)
        else:
            res = 0.0
            n = 2
            while True:
                term = 1.0 / (n ** K)
                if term < 1e-13:
                    break
                res += term
                n += 1
            print("{0:.9f}".format(res))