import sys

def main():
    X, K = map(int, sys.stdin.readline().split())
    if X == 1:
        result = 0.75 * (0.5) ** (K - 1)
        print("{0:.10f}".format(result))
    else:
        if K == 1:
            print("{0:.10f}".format(0.5))
        else:
            res = 0.0
            n = 2
            while True:
                term = 1.0 / (n ** K)
                res += term
                if term < 1e-12:
                    break
                n += 1
            print("{0:.10f}".format(res))

if __name__ == "__main__":
    main()