#include <bits/stdc++.h>
using namespace std;
bool isprime(long long int n) {
  if (n < 2) return false;
  for (long long int i = 2; i <= sqrt(n); i++)
    if (n % i == 0) return false;
  return true;
}
long long int countDivisors(long long int n) {
  long long int cnt = 0;
  for (long long int i = 1; i <= sqrt(n); i++) {
    if (n % i == 0) {
      if (n / i == i)
        cnt++;
      else
        cnt = cnt + 2;
    }
  }
  return cnt;
}
int main() {
  long long int n, k;
  string s;
  cin >> s;
  char ch = 'a';
  for (int i = 0; i < s.size(); i++) {
    if (ch == 'z') {
      if (s[i] <= ch) {
        s[i] = ch;
        ch = '0';
      }
    }
    if (s[i] <= ch) {
      s[i] = ch;
      ch++;
    }
  }
  if (ch == '0')
    cout << s;
  else
    cout << "-1";
  return 0;
}
