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