#include<stdio.h>

long long unsigned n, p;

int prim(long long unsigned x,long long unsigned y)
{
  while (x!=y)
    {
      if (x>y) x=x-y;
	else y-=x;
    }
  if (x==1) return 1;
  return 0;
}

void calcul()
{
  long long unsigned nr, contor=0;
  freopen("frac.in","r",stdin);
  scanf("%llu",&n,&p);
  nr=0;
  while (contor<p)
   {
     nr++;
     if (n%2==0 && nr%2==0);
	else	if (prim(n,nr)) contor++;
    }
  freopen("frac.out","w",stdout);
  printf("%llu",nr);
}

int main()
{
  calcul();
  return 0;
}