from itertools import chain


class UF_tree:
    def __init__(self, n):
        self.root = [-1] * (n + 1)
        self.rank = [0] * (n + 1)

    def find(self, x):
        if self.root[x] < 0:
            return x
        else:
            self.root[x] = self.find(self.root[x])
            return self.root[x]

    def isSame(self, x, y):
        return self.find(x) == self.find(y)

    def unite(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x == y:
            return
        elif self.rank[x] < self.rank[y]:
            self.root[y] += self.root[x]
            self.root[x] = y
        else:
            self.root[x] += self.root[y]
            self.root[y] = x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1

    def size(self, x):
        return -self.root[self.find(x)]


def prime_set(N):
    """
    Nまでの素数のsetを返す
    """
    if N < 4:
        return ({}, {}, {2}, {2, 3})[N]
    Nsq = int(N ** 0.5 + 0.5) + 1
    primes = {2, 3} | set(chain(range(5, N + 1, 6), range(7, N + 1, 6)))
    for i in range(5, Nsq, 2):
        if i in primes:
            primes -= set(range(i * i, N + 1, i * 2))
    return primes


N, P = map(int, input().split())
uf = UF_tree(N)
for p in prime_set(N):
    q = p * 2
    while q <= N:
        uf.unite(p, q)
        q += p

print(uf.size(P))