#include<iostream>
#include<string>
#include<fstream>
using namespace std;

int main()
{
	ifstream in;
	ofstream out;
	in.open("count.in");
	out.open("count.out");
	string num;
	char temp;
	in >> num;
	int res = 1;
	for(int i = 0;i < num.length()-1;i++)
	{
		for(int j = i+1;j < num.length();j++)
		{
			if(num[i] > num[j])
			{
				temp = num[i];
				num[i] = num[j];
				num[j] = temp;
			}
		}
	}
	for(int i = 0;i < num.length()-1;i++)
	{
		if(num[i] != num[i+1])
			res++;
	}
	out<<res<<endl;
	return 0;
}