#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 2;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  string str, temp, alp = "abcdefghijklmnopqrstuvwxyz";
  long long int i, j, n, m, ans = 0, k = 0, f = 0;
  cin >> str;
  for (i = 0; i < str.size(); ++i) {
    if (str[i] <= alp[k]) {
      str[i] = alp[k];
      ++k;
    }
    if (k == alp.size()) {
      f = 1;
      break;
    }
  }
  if (f)
    cout << str;
  else
    cout << "-1";
}
