#include <assert.h>
#include <ctype.h>
#include <float.h>
#include <limits.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>

#include <algorithm>
#include <bitset>
#include <complex>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;

#define SZ(a) (int)(a).size()
#define FOR(i,a,b) for (int i=(a); i<=(b); ++i)
#define REP(i,n) for (int i=0; i<(n); ++i)
#define ALL(c) c.begin(), c.end()
#define CLR(c,n) memset(c, n, sizeof(c))
#define MCPY(d, s) memcpy(d, s, sizeof(d))
#define TR(it, c) for (auto it = c.begin();it != c.end(); ++it)
#define CONTAIN(it, c) (c.find(it) != c.end())
typedef vector<int> VI;
typedef pair<int, int> PII;
template <class T> void checkmin(T &a, T b) { if (b<a) a=b; }
template <class T> void checkmax(T &a, T b) { if (b>a) a=b; }
typedef long long LL;
const int INF=0x3F3F3F3F;

const int N=100000;
int n, k;
int nf[N+1], np[N+1];
void init() {
  fill(nf, nf+N+1, 1);
  int p = 2;
  for (p = 2; p * p <= N; ++p) {
    if (nf[p] != 1) continue;
    int c = 1, pp = p;
    while (pp <= N) pp *= p, ++c;
    pp /= p;
    while (pp >= p) {
      for (int i = pp; i <= N; i += pp) {
        if (i / pp % p == 0) continue;
        nf[i] *= c;
      }
      pp /= p;
      --c;
    }
  }
  for (; p <= N; ++p) {
    if (nf[p] != 1) continue;
    for (int i = p; i <= N; i +=p) nf[i] *= 2;
  }
  FOR(i, 2, N) {
    if (nf[i] == 2) {
      np[i] = 1;
      continue;
    }
    for (int j = 2; j * j <= i; ++j) {
      if (i % j != 0) continue;
      np[i] = np[i/j] + 1;
      break;
    }
  }
}
int gcd(int a, int b) {
  while (b) {
    a %= b;
    swap(a, b);
  }
  return a;
}
int main(int argc, char *argv[]) {
  init();
  while (cin >> n >> k) {
    int ans = 0;
    for (int i = 2; i < n; ++i) {
      if (nf[i] <= nf[ans]) continue;
      if (np[gcd(n, i)] < k) continue;
      ans = i;
    }
    cout << ans << endl;
  }
}