#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  string s;
  cin >> s;
  string a = "";
  for (int i = 0; i < 26; i++) {
    a.push_back('a' + i);
  }
  int j = 0;
  for (int i = 0; i < s.size() && j < 26; i++) {
    if (s[i] <= a[j]) {
      s[i] = a[j];
      j++;
    }
  }
  if (j < 26) {
    cout << "-1";
  } else
    cout << s;
  return 0;
}
