#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e18;
const int mod = 1e9 + 7;
const int N = 1e5 + 10;
inline int add(int x, int y) {
  x += y;
  if (x >= mod) x -= mod;
  return x;
}
inline int mul(int x, int y) {
  x = (1LL * x * y) % mod;
  return x;
}
int main() {
  string s;
  cin >> s;
  string a = "abcdefghijklmnopqrstuvwxyz";
  long long k = 0;
  for (int i = 0; i <= s.size() - 1; ++i) {
    if (s[i] <= a[k]) {
      s[i] = a[k];
      k++;
    }
  }
  if (k == 26) {
    cout << s;
  } else {
    cout << -1;
  }
}
