import sys from math import gcd def input(): return sys.stdin.readline().strip() def list2d(a, b, c): return [[c] * b for i in range(a)] def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)] def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)] def ceil(x, y=1): return int(-(-x // y)) def INT(): return int(input()) def MAP(): return map(int, input().split()) def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)] def Yes(): print('Yes') def No(): print('No') def YES(): print('YES') def NO(): print('NO') sys.setrecursionlimit(10 ** 9) INF = 10 ** 18 MOD = 10 ** 9 + 7 EPS = 10 ** -10 def factorize(num: int) -> dict: """ 素因数分解 """ from math import sqrt from collections import Counter d = Counter() for i in range(2, int(sqrt(num))+1): while num % i == 0: num //= i d[i] += 1 if num == 1: break if num != 1: d[num] += 1 return d def divisors(N: int) -> set: """ 約数の列挙・個数 """ from math import sqrt s = {1, N} for i in range(2, int(sqrt(N))+1): if N % i == 0: s.add(i) s.add(N // i) return s N, K = MAP() ans = mx = 0 for i in range(1, N): g = gcd(i, N) cnt = sum(factorize(g).values()) if cnt >= K: ln = len(divisors(i)) if ln > mx: mx = ln ans = i elif ln == mx: if i < ans: ans = i print(ans)