#include<iostream>
#include<iomanip>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
//#include<fstream>
using namespace std;
int main(){
	long long j,sum=0,a,b,cnt=0;
	cin>>a>>b;
	for(long long i=1;i<=sqrt(100010);i++){
		for(j=2;j<=a;j++){
			if(a%j==0&&i%j==0)
				sum++;
		}
		if(sum==0)
			cnt++;
		sum=0;
		if(cnt==b){
			cout<<i;
			return 0;
		}		
	}
	return 0;
}