#include <stdio.h>
#include <stdlib.h>
#define N 7000000
bool prim[N];
int n,k,nr=0;
void ciur()
{
	int nn=n;
	for(int i=2;i<=nn;++i)
	{
		if(nn%i==0)
		{
			while(nn%i==0)
			{	nn/=i; }
			if(!prim[i])
				for(int j=i;j<N;j+=i)
					prim[j]=1;
		}
	}
}	
void scan()
{
	freopen("frac.in", "r",stdin);
	freopen("frac.out", "w",stdout);
	scanf("%d%d", &n,&k);
}
void solve()
{
	ciur();
	for(int i=1;;++i)
	{
		if(prim[i]==0)
			++nr;
		if(nr==k)
		{
			printf("%d\n", i);
			exit(0);
		}
	}
}
int main()
{
	scan();
	solve();
	return 0;
}