题解 | #字符个数统计#

#include <iostream>
#include <set>
#include <string>

using namespace std;

int main()
{
    string s;
    getline(cin, s);

    set<char> myset;
    for (char c : s)
    {
        myset.insert(c);
    }
    cout << myset.size() << endl;
}