#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  char ch = 'a';
  int i;
  for (i = 0; i < s.size(); i++)
    if (ch >= s[i]) {
      s[i] = ch;
      ++ch;
      if (s[i] == 'z') break;
    }
  if (ch == 123)
    cout << s;
  else
    cout << -1;
  return 0;
}
