#include <stdio.h>
#include <stdlib.h>
#include <math.h>

long long	N=0,P=0;


long long
	cmmdc(long long a,long long b)
	{
	long long r;
	
	r=a%b;
	while(r!=0)
		{
		a=b;
		b=r;
		r=a%b;
		}
	return b;
	}


int 
	main	(void)
	{
	long long  k=0,nrFractii=0;
			
	freopen("frac.in","r",stdin); 
	freopen("frac.out","w",stdout); 

	scanf("%lld %lld",&N,&P);
	if(N <= 1)
		{
		printf("%lld\n",P);
		return(0);
		}
	while(nrFractii != P)
		{
		if(cmmdc(2*k+1,N) == 1)
			++nrFractii;
		if(nrFractii == P)
			break;
		++k;
		}
	printf("%lld\n",2*k+1);
	return(0);
	}