#include <bits/stdc++.h>
using namespace std;
map<int, int> mp;
vector<int> inp;
int main() {
  ios_base::sync_with_stdio(false);
  string s;
  cin >> s;
  int curr = 0;
  for (int i = 0; i < s.length(); i++) {
    if (curr < 26 && s[i] - 'a' <= curr) {
      s[i] = 'a' + curr;
      curr++;
    }
  }
  if (curr >= 26)
    cout << s << endl;
  else
    cout << -1 << endl;
  return 0;
}
