void main()
{
	int n,k,m,re;
	int f(int n,int k,int time,int m);
	scanf("%d%d",&n,&k);
	m=0;
	do
	{
		m++;
		re=f(n,k,n,m);
    }while(re<0);
	printf("%d\n",re);
}
int f(int n,int k,int time,int m)
{
	int z,a;
	if(time>1)
	{
		z=f(n,k,time-1,m);
		if(z==-1||z%(n-1)!=0) a=-1;
		else a=n*z/(n-1)+k;

	}
	else a=m*n+k;
	return(a);
}