#include <bits/stdc++.h>
int main() {
  int t, i, c;
  char s[100100];
  for (scanf("%s", s), t = c = i = 0; c != 26 && s[i]; i++)
    s[i] <= 'a' + t && (s[i] = 'a' + t, c++, t++);
  puts(c == 26 ? s : "-1");
}
