#include <bits/stdc++.h>
using namespace std;
string s;
int main() {
  cin >> s;
  int cnt = 0;
  for (int i = 0; i < s.size(); i++) {
    if (cnt == 26) break;
    if (s[i] - 'a' <= cnt) {
      s[i] = 'a' + cnt;
      cnt++;
    }
  }
  if (cnt < 26)
    printf("-1\n");
  else
    cout << s << endl;
  return 0;
}
