func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int n;     cin >> n;     string s;     cin >> s;     set<char> S;     int ans = 0;     for (int i = 0; i <= s.size(); ++i) {       if (i == s.size() || isupper(s[i])) {         ans = max(ans, (int)S.size());         S.clear();       } else {         S.insert(s[i]);       }     }     cout << ans << endl;     return 0;   }   