#include<fstream>

using namespace std;

long long n,p,c=1,z;

int main()
{
    ifstream fin("frac.in");
    ofstream fout("frac.out");
int i,a,b,r;
fin>>n>>p;
for(i = 2;;i++)
{
      a = n;
      b = i;
while(a%b)
{
   r=a%b;
   a=b;
   b=r;
}
if(b == 1)
{
     c++;
     z = i;
     if(c == p)
     {fout<<z;
     return 0;
     }
}
}


fin.close();
fout.close();

return 0;

}