n,k = map(int,input().split())
yaku = [0]*n
for i in range(2,n):
    for j in range(i,n,i):
        yaku[j] += 1

cnt = [0]*n
for i in range(n):
    if yaku[i] == 1 and n%i==0:
        nn = n
        v = i
        while nn%i==0:
            nn //= i
            for j in range(v,n,v):
                cnt[j] += 1
            v *= i

ans = 0
val = 0
for i in range(n):
    if cnt[i] >= k and val < yaku[i]:
        val = yaku[i]
        ans = i
print(ans)