import sys

def main():
    X, K = map(int, sys.stdin.readline().split())
    if X == 1:
        result = (3.0 / 4) * (0.5 ** (K - 1))
        print("{0:.10f}".format(result))
    elif X == 2:
        if K == 1:
            print("0.5")
        else:
            # Compute sum_{n=2}^infty 1/n^K
            s = 0.0
            n = 2
            while True:
                term = 1.0 / (n ** K)
                if term < 1e-15:  # Very small term, stop adding
                    break
                s += term
                n += 1
            print("{0:.10f}".format(s))

if __name__ == "__main__":
    main()