#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  string t = "abcdefghijklmnopqrstuvwxyz";
  string s1 = s;
  int k = 0;
  char x = 'a', y = 'a';
  int counter = 0;
  for (int i = 0; i < s.size(); ++i) {
    if (s[i] <= x) {
      s[i] = x;
      if (x == 'z') {
        counter = 1;
        break;
      }
      x = x + 1;
    }
  }
  if (counter == 1)
    cout << s;
  else
    cout << -1;
  return 0;
}
