#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  if (s.length() < 26) {
    cout << -1 << endl;
    return 0;
  }
  int j = -1;
  for (int i = 0; i < s.length(); i++)
    if (s[i] == 'a') {
      j = i + 1;
      break;
    }
  if (j == -1) {
    cout << -1 << endl;
    return 0;
  }
  for (char c = 'b'; c <= 'z'; c++) {
    bool f = 0;
    for (int i = j; i < s.length(); i++) {
      if (s[i] <= (char)(c - 1)) {
        s[i] = c, j = i + 1, f = 1;
        break;
      }
      if (s[i] == (char)(c)) {
        j = i + 1, f = 1;
        break;
      }
    }
    if (f == 0) {
      cout << -1 << endl;
      return 0;
    }
  }
  cout << s << endl;
}
