#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cout.tie(0);
  cin.tie(0);
  string s;
  cin >> s;
  long long n = s.size();
  long long curr = 0;
  for (long long i = 0; i < n; i++) {
    if (s[i] - 'a' > curr) continue;
    s[i] = (char)('a' + curr);
    curr++;
    if (curr > 25) break;
  }
  if (curr > 25)
    cout << s;
  else
    cout << -1;
}
