#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  if (s.length() < 26) {
    return cout << -1 << endl, 0;
  }
  bool vis[26] = {false};
  char cur = 'a';
  for (int i = 0; i < s.length(); i++) {
    if (s[i] <= cur) {
      s[i] = cur;
      cur++;
      vis[cur - 'a' - 1] = true;
      if (cur > 'z') break;
      continue;
    }
  }
  for (int i = 0; i < 26; i++) {
    if (!vis[i]) {
      return cout << -1 << endl, 0;
    }
  }
  cout << s << endl;
  return 0;
}
