#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  string s;
  cin >> s;
  string alpha = "abcdefghijklmnopqrstuvwxyz";
  int size = s.size();
  int k = 0;
  for (int i = 0; i < size; ++i) {
    if (s[i] <= alpha[k]) {
      s[i] = alpha[k];
      k++;
    }
  }
  if (k == 26) {
    cout << s << '\n';
    return 0;
  } else
    return cout << -1, 0;
  return 0;
}
