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

int main() {
    int n,k;
    cin>>n>>k;
    map<int,int> pf[n+1];
    for (int i=1;i<=n;i++) {
        int t=i;
        for (int j=2;j*j<=t;j++)
            while (t%j==0) {
                pf[i][j]++;
                t/=j;
            }
        if (t>1) pf[i][t]++;
    }
    int ans=0;
    int mx=0;
    for (int i=1;i<n;i++) {
        int g=gcd(i,n);
        int sum=0;
        for (auto p:pf[g]) sum+=p.second;
        if (sum<k) continue;
        int div=1;
        for (auto p:pf[i])
            div*=p.second+1;
        if (div>mx) {
            ans=i;
            mx=div;
        }
    }
    cout<<ans<<endl;
    return 0;
}