#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  char ch = 'a';
  if (s.size() < 26) {
    cout << "-1" << endl;
    return 0;
  } else {
    for (int i = 0; i < s.size(); i++) {
      if (s[i] <= ch) {
        s[i] = ch;
        ch++;
        if (ch == 'z' + 1) {
          break;
        }
      }
    }
  }
  char check = 'z';
  check++;
  if (ch == check) {
    cout << s << endl;
  } else {
    cout << "-1" << endl;
  }
  return 0;
}
