#include <bits/stdc++.h>
using namespace std;
char A[123456];
int main() {
  scanf("%s", A);
  int len = strlen(A);
  char Aim = 'a';
  for (int i = 0; i < len; i++) {
    if (A[i] == Aim)
      Aim += 1;
    else if (A[i] < Aim)
      A[i] = Aim, Aim += 1;
    if (Aim > 'z') break;
  }
  if (Aim <= 'z')
    cout << -1 << '\n';
  else
    cout << A << '\n';
}
