#include<fstream>
using namespace std;
int i,s,n,r,k=0,p,cmmdc,m;
int main ()
{
ifstream in ("frac.in");
ofstream out("frac.out");
in>>n;
in>>p;
for(i=1;i<=10000;i++)
{s=i/n;
r=i;
m=n;
   while (r!=m)
     { if(r>m) r=r-m;
       if(m>r) m=m-r;
       cmmdc=r; }
if ((cmmdc==1)&&(i!=n)) k++;
if (k==p) { out<<i;break;} }
in.close ();
out.close ();
return 0;
}