#include<bits/stdc++.h>
using namespace std;

int p[]= {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317};
int t=66,i,j;
int s[100000],y[100000]={};

int gcd (int a, int b){
int c;
while(a){c=a;a=b%a;b=c;}
return b;}

void a(){
for(i=0;i-t;++i)s[p[i]]=1;
for(i=4;i-100000;++i)for(j=0;p[j]*p[j]<=i;++j){
if(i%p[j]==0){s[i]=s[i/p[j]]+s[p[j]];break;}
if((p[j]+1)*(p[j]+1)>i)s[i]=1;}}

void b(){
for(i=1;i-100000;++i)for(j=1;j*j<=i;++j){
if(j*j==i)++y[i];else if(i%j==0)y[i]+=2;}}

int main(){
int n,k,m=0,q;
cin>>n>>k;
a();b();
for(i=2;i-n;++i)if(s[gcd(i,n)]>=k&&y[i]>m){
m=y[i];q=i;}
cout<<q<<endl;}