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