#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  if ((int)s.size() < 26) {
    cout << -1;
    return 0;
  }
  char cur = 'a';
  bool fg = 0;
  for (int i = 0; i < (int)s.size(); i++) {
    if (s[i] <= cur) {
      if (cur == 'z') {
        s[i] = cur;
        fg = 1;
        break;
      } else
        s[i] = cur;
      cur++;
    }
  }
  if (cur == 'z' && fg)
    cout << s;
  else
    cout << -1;
  return 0;
}
