#include <bits/stdc++.h>
#define FOR(v, a, b) for(int v = (a); v < (b); ++v)
#define FORE(v, a, b) for(int v = (a); v <= (b); ++v)
#define REP(v, n) FOR(v, 0, n)
#define REPE(v, n) FORE(v, 0, n)
#define REV(v, a, b) for(int v = (a); v >= (b); --v)
#define ALL(x) (x).begin(), (x).end()
#define ITR(it, c) for(auto it = (c).begin(); it != (c).end(); ++it)
#define RITR(it, c) for(auto it = (c).rbegin(); it != (c).rend(); ++it)
#define EXIST(c,x) ((c).find(x) != (c).end())
#define LLI long long int
#define fst first
#define snd second

#ifdef DEBUG
#include <misc/C++/Debug.cpp>
#else
#define dump(x) ((void)0)
#endif

#define gcd __gcd

using namespace std;
template <class T> constexpr T lcm(T m, T n){return m/gcd(m,n)*n;}

template <typename I> void join(ostream &ost, I s, I t, string d=" "){for(auto i=s; i!=t; ++i){if(i!=s)ost<<d; ost<<*i;}ost<<endl;}
template <typename T> istream& operator>>(istream &is, vector<T> &v){for(auto &a : v) is >> a; return is;}
template <typename T, typename U> istream& operator>>(istream &is, pair<T,U> &p){is >> p.first >> p.second; return is;}

template <typename T, typename U> bool chmin(T &a, const U &b){return (a>b ? a=b, true : false);}
template <typename T, typename U> bool chmax(T &a, const U &b){return (a<b ? a=b, true : false);}
template <typename T, size_t N, typename U> void fill_array(T (&a)[N], const U &v){fill((U*)a, (U*)(a+N), v);}

vector<pair<int,int>> prime_factorize(int n){
  vector<pair<int,int>> res;
  for(LLI i=2LL; i*i<=n; ++i){
    if(n % i) continue;
    int c = 0;
    while(n % i == 0){
      n /= i;
      ++c;
    }
    res.push_back({i,c});
  }
  if(n!=1) res.push_back({n,1});
  return res;
}




int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  int N,K;
  while(cin >> N >> K){

    vector<int> pfcnt(N+1);
    vector<int> dvcnt(N+1,1);
    FORE(i,1,N){
      auto p = prime_factorize(i);
      for(auto &x : p){
	pfcnt[i] += x.snd;
	dvcnt[i] *= (x.snd+1);
      }
    }

    vector<int> ans(N+1);
    
    FOR(i,1,N){
      int g = gcd(N,i);
      if(pfcnt[g] >= K){
	ans[i] = dvcnt[i];
      }
    }

    cout << max_element(ALL(ans))-ans.begin() << endl;
  }
  
  return 0;
}