#include <bits/stdc++.h>
using namespace std;
long long modularExponentiation(long long x, long long n, long long mm) {
  long long result = 1;
  while (n > 0) {
    if (n % 2 == 1) result = (result * x) % mm;
    x = (x * x) % mm;
    n = n / 2;
  }
  return result;
}
void solve() {
  string s;
  cin >> s;
  char c = 'a';
  for (long long i = 0; i < (long long)s.size(); i++) {
    if (s[i] <= c && c <= 'z') s[i] = c++;
  }
  c--;
  if (c == 'z')
    cout << s;
  else
    cout << -1;
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long t = 1;
  while (t--) solve();
}
