#include<fstream>

using namespace std;

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


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

return 0;

}