func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     string s;     cin >> s;     char cur =  a ;     vector<char> res(s.size());     for (int i = 0; i < s.size(); i++) {       if (cur >  z ) {         res[i] = s[i];       } else if (s[i] <= cur) {         res[i] = cur;         cur++;       } else {         res[i] = s[i];       }     }     if (cur >  z ) {       for (auto elem : res) {         cout << elem;       }     } else {       cout << -1;     }   }   