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