#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  string s;
  cin >> s;
  int cnt = 0;
  int i = 0;
  for (; i < s.size() && cnt < 26; i++) {
    int cur = ((int)s[i]) - 97;
    if (cur <= cnt) {
      s[i] = (char)(cnt + 97);
      ++cnt;
    }
  }
  if (cnt == 26)
    cout << s << endl;
  else
    cout << -1 << endl;
  return 0;
}
