#include <bits/stdc++.h>
using namespace std;
int const MAXN = 5005;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  string cad;
  cin >> cad;
  int pos = 0;
  int n = cad.size();
  for (int i = 0; i < n; ++i) {
    if (pos == 26) break;
    char act = (char)('a' + pos);
    if (cad[i] <= act) {
      cad[i] = act;
      pos++;
    }
  }
  if (pos != 26)
    cout << -1 << '\n';
  else
    cout << cad << '\n';
  return 0;
}
