#include<fstream.h>
long a,er[12000000000]/*<==limita n-ului aici*/,d[101];
int main()
{int j,max=0,n,p,i;
cin>>n>>p;
int cn=n;
for(i=2;i<=cn/2;i++)
	if(n%i==0)
	 {d[i]=1;
	 n=n/i;
   i=1;
    if(i>max)
		max=i;}
d[cn]=1;
a=1;
for(i=2;i<=101;i++)
	if(er[i]==0&&d[i]==1)
	 for(j=i;j<=101;j=j+i)
		er[j]=1;
	else
	 {if(er[i]!=1)
		a++;
		if(a==p)
		 {cout<<i;
		 i=102;}}
cout<<endl;
return 0;}