# 難しく考えすぎたらしい
# 全探索すればいい
# N<10**5と小さい
# 素因数分解はdefaultdict型に改造した

# 辞書型に改造した
from collections import defaultdict
def factorization(n):
    arr = defaultdict(int)
    temp = n
    for i in range(2, int(-(-n**0.5//1))+1):
        if temp%i==0:
            cnt=0
            while temp%i==0:
                cnt+=1
                temp //= i
            arr[i] = cnt
    if temp!=1:
        arr[temp] = 1
    #if arr==[]: #素因数として1が加えられないようにした
    #    arr.append([n, 1])
    return arr

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

candidates = []
for i in range(1, N):
    i_factors = factorization(i)
    common = 0
    for d in N_factors:
        common += min(N_factors[d], i_factors[d])
    if common >= K:
        div_count = 1
        for di in i_factors:
            div_count *= (i_factors[di]+1)
        candidates.append([div_count, i])
    
candidates.sort(key = lambda x:(-x[0], x[1]))
print(candidates[0][1])
#print(candidates)