#include<stdio.h>
#define maxn 12000005
long long i,j,n,p,k
int a[maxn];
FILE *f,*g;
int main()
{f=fopen("frac.in","r");
g=fopen("frac.out","w");
fscanf(f,"%lld %lld",&n,&p);
for(i=2;i<=n&&k<=p;i++)
if(a[i]==0)
{for(j=i;j<=n;a[j]=1,j+=i);
if(n%i==0 || i%n==0)
k++;}
fprintf(g,"%lld",i);
fclose(f);
fclose(g);
return 0;}