#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j, k, n;
  string s;
  cin >> s;
  n = s.size();
  int x = 25;
  for (i = n - 1; i >= 0; i--) {
    if (s[i] <= 'a' + x) {
      s[i] = 'a' + x;
      x--;
    }
  }
  if (x == -1) {
    cout << s;
  } else {
    cout << "-1";
  }
}
