#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  string s;
  cin >> s;
  char cur = 'a';
  for (char &c : s) {
    if (c <= cur) {
      c = cur;
      cur++;
      if (cur - 'a' == 26) {
        break;
      }
    }
  }
  if (cur - 'a' == 26) {
    cout << s << endl;
  } else {
    cout << -1 << endl;
  }
  return 0;
}
