using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace question_2
{
    class Program
    {
        static void Main(string[] args)
        {
            string a = Console.ReadLine();
            int length = a.Length;
            int count = 0;
            for (int i = 0; i < length; i++)
            {
                if (char.IsLower(a[i]))
                {
                    bool enterbefore = false;
                    for (int k = 1; k <= i;k++)
                    {

                        if (a[i] == a[k])
                        {
                            break;
                            enterbefore = true;
                        }
                    }
                    if (!enterbefore)
                    {
                        count++;
                    }
                }
            }

            Console.WriteLine("The Answer is "+count);
            Console.ReadLine();
        }
    }
}