import sys

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