寒假训练

#include<iostream>
#include<string>
#include <set>
using namespace std;
int main()
{
	string s;
	set<char> t;
	int nl;
	while (cin >> s)
	{
		nl = s.length();
		for (int i = 0; i < nl; i++)
		{
			if (s[i] != '{'&&s[i] != '}'&&s[i] != ',') t.insert(s[i]);
		}
	}
	cout << t.size() << endl;
	return 0;
}