import sys

def main():
    X, K = map(int, sys.stdin.readline().split())
    
    if X == 1:
        result = 1.0 - (0.5 ** (K + 1))
        print("{0:.9f}".format(result))
    else:
        # Compute sum_{k=2}^infty 1/k^K
        sum_val = 0.0
        k = 2
        while True:
            term = 1.0 / (k ** K)
            if term < 1e-12:
                break
            sum_val += term
            k += 1
        print("{0:.9f}".format(sum_val))
    
if __name__ == "__main__":
    main()