#include <bits/stdc++.h>
using namespace std;
void fast() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
}
const int N = 1e5 + 5;
int dp[N][26];
string s;
int go(int i, int letter) {
  if (letter > 26) return 0;
  if (i == s.size()) {
    return (letter == 0);
  }
  int &ret = dp[i][letter];
  if (~ret) return ret;
  ret = go(i + 1, letter);
  if ((s[i] - 'a') <= letter)
    ret = min(ret, go(i + 1, letter + 1) + letter - (s[i] - '0'));
  return ret;
}
int main() {
  fast();
  cin >> s;
  int letter = 0;
  for (int i = 0; i < s.size(); ++i) {
    if (letter == 26) break;
    if (letter == (s[i] - 'a')) {
      letter++;
      continue;
    } else if (letter > (s[i] - 'a')) {
      s[i] = (letter + 'a');
      letter++;
    }
  }
  if (letter != 26)
    cout << -1 << "\n";
  else
    cout << s << "\n";
}
