#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  char cur = 'a';
  vector<char> res(s.size());
  for (int i = 0; i < s.size(); i++) {
    if (cur > 'z') {
      res[i] = s[i];
    } else if (s[i] <= cur) {
      res[i] = cur;
      cur++;
    } else {
      res[i] = s[i];
    }
  }
  if (cur > 'z') {
    for (auto elem : res) {
      cout << elem;
    }
  } else {
    cout << -1;
  }
}
