func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     string str;     cin >> str;     int t;     cin >> t;     int type, pos, l, r;     char c;     set<int> s[26];     for (int i = 0; i < str.length(); i++) s[str[i] -  a ].insert(i + 1);     while (t--) {       cin >> type;       if (type == 1) {         cin >> pos >> c;         s[str[pos - 1] -  a ].erase(pos);         s[c -  a ].insert(pos);         str[pos - 1] = c;       } else {         cin >> l >> r;         int count = 0;         for (int i = 0; i < 26; i++)           if (s[i].lower_bound(l) != s[i].upper_bound(r)) count++;         cout << count << endl;       }     }     return 0;   }   