#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int i, c = 0;
  string a = "abcdefghijklmnopqrstuvwxyz";
  for (i = 0; i < s.length() && c < 26; i++) {
    if (a[c] >= s[i]) {
      s[i] = a[c];
      c++;
    }
  }
  if (c == 26)
    cout << s;
  else
    cout << "-1";
  return 0;
}
