#include <iostream>
#include <fstream>
 
using namespace std;
 
ifstream in("frac.in");
ofstream out("frac.out");
 
int const nmax=2000005;
long long int n=nmax,pr=2,p,pp[nmax],m;
unsigned char a[nmax];
int main(){
	pp[1]=1;
	
 
in >>m>>p;
 if(m %2==1){
 	pp[2]=2;
 	pr=3;
 }
for(int i=3;i<=n;i=i+2){
	if(a[i>>4] & (1<<((i>>1) & 7))) continue;
	if( m % i !=0){
	
	    pp[pr]=i;
	    if(pr==p){
	    out <<pp[pr];	
	    break;
		}
		pr++;
}
		
	for(int j=i*3;j<=n;j+=i+i){
	a[j >> 4] |= 1 << ((j>>1) & 7);
}


}

}