import sys

def main():
    X, K = map(int, sys.stdin.readline().split())
    if X == 1:
        ans = 1.0 - 1.0 / (2 ** (K + 1))
        print("{0:.9f}".format(ans))
    else:
        if K == 1:
            print("0.500000000")
        else:
            s = 0.0
            n = 2
            while True:
                term = 1.0 / (n ** K)
                if term < 1e-15 * s:
                    break
                s += term
                n += 1
            print("{0:.9f}".format(s))

if __name__ == '__main__':
    main()