#include<fstream.h>
ifstream intrare ("frac.in");
ofstream iesire ("frac.out");
int main()
{
	long long unsigned n,c,p,nr=0,t,f,i,a,b;
	intrare>>n>>p;
	i=1;
	if(n%2==0) f=2;
	else f=1;
	while(nr!=p)
	{       b=i;
		a=n;
		while(b!=0)
		{
			c=a%b;
			a=b;
			b=c;
		}
		if(a==1) {nr++; t=i;}
		i+=f;
	}
	iesire<<t;
	return 0;
}