#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  long long int sz = s.size(), i;
  char x = 'a';
  for (i = 0; i < sz && x <= 'z'; i++) {
    if (s[i] <= x) {
      s[i] = x;
      x++;
    }
  }
  if (x > 'z')
    cout << s << endl;
  else
    cout << -1 << endl;
  return 0;
}
