#include <bits/stdc++.h>
using namespace std;
int v = 97, i;
string s;
int main() {
  cin >> s;
  while (s[i] && v <= 122) {
    if (s[i] <= v) s[i] = v++;
    i++;
  }
  cout << ((v - 123) ? "-1" : s);
}
