#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0;i<((int)(n));i++)
#define reg(i,a,b) for(int i = ((int)(a));i<=((int)(b));i++)
#define irep(i,n) for(int i = ((int)(n)-1);i>=0;i--)
#define ireg(i,a,b) for(int i = ((int)(b));i>=((int)(a));i--)
typedef long long ll;

/*
*/

ll n,k,divisor_num[100010],prime_num[100010],ans=0,ans_num=0;
vector<ll> fact[100010];

void factoring(ll n,vector<ll> v[]){
	ll visit[300010]={};
	reg(i,2,n){
		if(visit[i]==0){
			reg(j,1,n){
				if(j*i>n)break;
				visit[i*j]=1;
				v[i*j].push_back(i);//素因数リスト（重複は含まず）
			}
		}
	}
}

void calc_divisor_num(ll n, vector<ll> fact[], ll divisor_num[]){
	reg(i,2,n){
		ll m=i;
		divisor_num[i]=1;
		rep(j,fact[i].size()){
			ll t=0;
			while(m%fact[i][j]==0){
				m/=fact[i][j];
				t++;
			}
			divisor_num[i]*=(t+1);
		}
	}
}

void calc_prime_num(ll n, vector<ll> fact[], ll prime_num[]){
	reg(i,1,n){
		ll m=i;
		prime_num[i]=0;
		rep(j,fact[i].size()){
			while(m%fact[i][j]==0){
				m/=fact[i][j];
				prime_num[i]++;
			}
		}
	}
}

//ユークリッドの互除法
long long gcd(long long a,long long b){
	if(b==0)return a;
	return gcd(b,a%b);
}

void init(){
	cin>>n>>k;
	factoring(n,fact);
	calc_divisor_num(n,fact,divisor_num);
	calc_prime_num(n,fact,prime_num);
}

int main(void){
	init();
	reg(i,1,n-1){
		ll g = gcd(i,n);
		if(prime_num[g]>=k && ans_num<divisor_num[i]){
			ans_num = divisor_num[i];
			ans = i;
		}
	}
	cout<<ans<<endl;
	return 0;
}