class Program
    {
        static void Main(string[] args)
        {
            long n = long.Parse(Console.ReadLine());
            
            var divisors = new List<long>();

            for(long i = 1; i <= n; i++)
            {
                if(n%i == 0)
                {
                    divisors.Add(i);
                }
            }

            long sum = 0;
            foreach (var divisor in divisors)
            {
                sum += divisor;
            }
            Console.WriteLine(sum);
        }
    }