#include <bits/stdc++.h>
using namespace std;
long long x, v, n, m;
char znak, cur = 'a';
string ans, slowo;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  ans = "";
  cin >> slowo;
  for (int a = 0; a < slowo.size(); a++) {
    znak = slowo[a];
    v = znak;
    if (cur > 'z') {
      ans += znak;
      continue;
    }
    if (v <= cur)
      ans += cur, cur++;
    else
      ans += znak;
  }
  if (cur > 'z')
    cout << ans << endl;
  else
    cout << "-1";
  return 0;
}
