#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  string s;
  cin >> s;
  char cur = 'a';
  bool ok = 0;
  for (long long(i) = (0); (i) < (s.length()); (i)++)
    if (s[i] <= cur) {
      s[i] = cur;
      if (cur != 'z')
        cur++;
      else
        ok = 1;
    }
  if (ok)
    cout << s << "\n";
  else
    cout << -1 << "\n";
  return 0;
}
