#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000007;
const int INF = 2000 * 1000 * 1000 + 5;
const int MAX = 1005;
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
long long lcm(long long a, long long b) {
  long long temp = gcd(a, b);
  return temp ? (a / temp * b) : 0;
}
template <typename T>
T modpow(T base, T exp, T modulus) {
  base %= modulus;
  T result = 1;
  while (exp > 0) {
    if (exp & 1) result = (result * base) % modulus;
    base = (base * base) % modulus;
    exp >>= 1;
  }
  return result;
}
inline bool isInteger(const std::string& s) {
  if (s.empty() || ((!isdigit(s[0])) && (s[0] != '-') && (s[0] != '+')))
    return false;
  char* p;
  strtol(s.c_str(), &p, 10);
  return (*p == 0);
}
int main() {
  string s;
  cin >> s;
  char target = 'a';
  for (int i = 0; i < s.length() && target <= 'z'; i++) {
    if (s[i] <= target) s[i] = target++;
  }
  if (target == 'z' + 1)
    cout << s << endl;
  else
    cout << -1 << endl;
  return 0;
}
