from collections import defaultdict
import math

def Sieve_of_Eratosthenes(maxA):
    lst = [-1]*(maxA+1)
    lst[0] = 0
    lst[1] = 1
    for i in range(2, maxA+1):
        if lst[i] == -1:
            for g in range(i, maxA+1, i):
                if lst[g] == -1:
                    lst[g] = i
    return lst

def factorization(n):
    d = defaultdict(int)
    now = n
    while True:
        if now == lst[now]:
            if now != 1:
                d[now] += 1
            break
        r = lst[now]
        while now % r == 0:
            now //= r
            d[r] += 1
    return d

num = 0
MAX = 0
n, k = map(int, input().split())
lst = Sieve_of_Eratosthenes(n)
for i in range(1, n):
    common = sum(factorization(math.gcd(i, n)).values())
    if common >= k:
        v = factorization(i).values()
        ans = 1
        for g in v:
            ans *= (g+1)
        if num < ans:
            num = ans
            MAX = max(MAX, i)

print(MAX)