from collections import Counter
from math import gcd


def factorize(n):
    p = 2
    while p * p <= n:
        while n % p == 0:
            yield p
            n //= p
        p += 1
    if n > 1:
        yield n


def number_of_divisors(n: int) -> int:
    res = 1
    for k, v in Counter(factorize(n)).items():
        res *= v+1

    return res


N, K = map(int, input().split())

dmax = 0
ans = 0
for i in range(1, N):
    g = gcd(i, N)
    np = len(list(factorize(g)))
    if np >= K:
        nd = number_of_divisors(i)
        if dmax < nd:
            dmax = nd
            ans = i

print(ans)