#include<iostream>

#include<cstdio>

#include<cstring>

#include<cstdlib>

#include<string>

#include<cmath>

#include<ctime>

#include<algorithm>

#include<map>

#include<set>

#include<queue>

#include<iomanip>

using namespace std;

#define ll long long

#define db double

#define up(i,j,n) for(ll i=j;i<=n;i++)

#define pii pair<ll,ll>

#define uint unsigned ll

#define FILE "dealing"

ll read(){

	ll x=0,f=1,ch=getchar();

	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}

	while(ch>='0'&&ch<='9'){x=(x<<1)+(x<<3)+ch-'0';ch=getchar();}

	return x*f;

}

template<class T> bool cmax(T& a,T b){return a<b?a=b,true:false;}

template<class T> bool cmin(T& a,T b){return a>b?a=b,true:false;}

const ll maxn=10100,limit=128;

ll n,k;

struct node{

	ll v;

	ll t,pre,p;

	node(ll v=0,ll t=0,ll pre=0,ll p=0):v(v),t(t),pre(pre),p(p){}

}temp;

bool operator<(const node& a,const node& b){return a.v<b.v;}

priority_queue<node> q;

bool b[maxn];

ll prime[maxn],tail=0;

void getprime(){

	up(i,2,128){

		if(!b[i])prime[++tail]=i;

		for(ll j=1;j<=tail&&i*prime[j]<=128;j++){

			b[i*prime[j]]=1;

			if(i%prime[j]==0)break;

		}

	}

	up(i,1,tail){

		ll t=1;

		up(j,1,128){

			if((db)t*prime[i]>n)break;//注意可能爆long long

			q.push(node(t*=prime[i],j,i-1,i));

		}//              data     mi   pre now

	}

}

int main(){

	freopen(FILE".in","r",stdin);

	freopen(FILE".out","w",stdout);

	n=read(),k=read();

	getprime();

	while(k--){

		temp=q.top();q.pop();

		if(temp.t>1){

			for(ll i=temp.pre;i>=1;i--){

				q.push(node(temp.v/prime[temp.p]*prime[i],temp.t-1,i,temp.p));

			}

		}

	}

	printf("%lld\n",temp.v);

	return 0;

}