#include <bits/stdc++.h>
using namespace std;
int a[1234567];
int main() {
  string s;
  cin >> s;
  int cnt1 = 0;
  int beg, beg1;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] > cnt1 + 'a') continue;
    cnt1++;
    s[i] = (char)('a' + cnt1 - 1);
    if (cnt1 == 26) break;
  }
  if (cnt1 == 26) return cout << s, 0;
  puts("-1");
}
