#include <bits/stdc++.h>
using namespace std;
string a;
int n, m;
const string s = "abcdefghijklmnopqrstuvwxyz";
void Nhap() {
  cin >> a;
  n = a.length();
  m = 26;
}
void process() {
  int j = 0;
  for (int i = 0; i < n; ++i) {
    if (a[i] <= s[j]) {
      a[i] = s[j];
      ++j;
    }
  }
  if (j == 26)
    cout << a;
  else
    cout << -1;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  Nhap();
  process();
  return 0;
}
