#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  long long int i, c = -1, d, f;
  char e;
  for (i = 0; i < s.size(); i++) {
    if (s[i] == 'a') {
      c = i;
      break;
    }
  }
  if (c == -1) {
    cout << "-1" << endl;
    return 0;
  }
  vector<char> v;
  for (i = 0, d = 97; i <= 25; i++, d++) {
    e = (char)d;
    v.push_back(e);
  }
  for (i = c + 1, d = 1; i < s.size(); i++) {
    f = v[d];
    if ((int)s[i] <= f && d < v.size()) {
      s[i] = v[d];
      d++;
    }
  }
  if (d > v.size() - 1) {
    cout << s << endl;
  } else {
    cout << "-1" << endl;
  }
}
