N,p = input().split()
N = int(N)
p = float(p)
A0 = list(range(2,N+1))

def E(A):
    if len(A)==0:
        return 0
    a = A[0]
    A_s = [i for i in A if i%a != 0]
    A_f = A[1:]
    return p*(E(A_s)+1)+(1-p)*(E(A_f)+1)

print(E(A0))