#include<fstream>

using namespace std;

ifstream fin("frac.in");
ofstream fout("frac.out");

short b[10000000];
void citire(long long &n,long long &p)
{
     fin>>n;
     fin>>p;
     
fin.close();
}
void umple(int q,short b[1000000],long long n,long long p)
{
     int j;
     for(j = q; j <= 100000;j+=2)
     if(j%q == 0)
     b[j] = 1;
}
void era(short b[1000000],long long n,long long p)
{
     int i;
     long long z;
z = n;
     for(i =2; i <= z; i++)
     if(n%i == 0)
     {
            umple(i,b,n,p);
            while(n%i == 0)
                      n/=i;
     }
}
void gasire(long long p,short b[1000000],long long n)
{
     long long q=0,i;
                for(i = 1 ; i <= 1000000;i++)
                if(b[i] == 0)
                {
                        q++;
                        if(q == p)
                        break;
                }
     fout<<i-1;
}
int main()
{
    long long  n,p;
    citire(n,p);
   era(b,n,p);
    gasire(p,b,n);

fout.close();

return 0;
}