public static int getTotalX(List<int> a, List<int> b)
    {
    
        List<int> GetFactoresMutuos()
        {
            var max = b.Min(x => x);
            List<int> factores = new List<int>();
            for (int i = 1; i <= max; i++)
            {
                if(b.All(el => el % i == 0))
                    factores.Add(i);
            }

            return factores;
        }

        List<int> GetPossiveisR(List<int> factoresParaTestar)
        {
            return factoresParaTestar.Where(f => a.All(elA => f % elA == 0)).ToList() ;
        }

        var fatores = GetFactoresMutuos();
        var possivesR = GetPossiveisR(fatores);

        return possivesR.Count();
    }