# -*- coding: utf-8 -*-

import random
import time

start = time.clock()

N, p = map(float, raw_input().split())
N = int(N)

QQ = 10 ** 6
total = 0
q = 0

# モンテカルロ法

while time.clock() - start < 0.8:

    prime = [True] * (N + 1)
    prime[0] = prime[1] = False

    for v in xrange(2, N + 1):
        if not prime[v]:
            continue
        if random.random() <= 1 - p:
            for i in xrange(v + v, N + 1, v):
                prime[i] = False

    total += sum(prime)
    q += 1

print 1.0 * total / q