#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  char c = 'a';
  for (int i = 0; i < s.length(); i++) {
    if (s[i] <= c) {
      s[i] = c;
      c = c + 1;
    }
    if (c > 'z') break;
  }
  if (c > 'z')
    cout << s;
  else
    cout << "-1";
  return 0;
}
