#include <bits/stdc++.h>
using namespace std;
string s, c = "abcdefghijklmnopqrstuvwxyz";
bool t;
int main() {
  cin >> s;
  int o = 0;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] <= c[o]) {
      s[i] = c[o];
      o++;
    }
    if (o == 26) {
      cout << s;
      return 0;
    }
  }
  cout << "-1";
  return 0;
}
